x/imagegen: clean up image generation code (#13725)

llm/server.go

@@ -1464,6 +1464,11 @@ type CompletionRequest struct {
 
 	// TopLogprobs specifies the number of most likely alternative tokens to return (0-20)
 	TopLogprobs int
+
+	// Image generation fields
+	Width  int32 `json:"width,omitempty"`
+	Height int32 `json:"height,omitempty"`
+	Seed   int64 `json:"seed,omitempty"`
 }
 
 // DoneReason represents the reason why a completion response is done
@@ -1512,6 +1517,11 @@ type CompletionResponse struct {
 
 	// Logprobs contains log probability information if requested
 	Logprobs []Logprob `json:"logprobs,omitempty"`
+
+	// Image generation fields
+	Image []byte `json:"image,omitempty"` // Generated image
+	Step  int    `json:"step,omitempty"`  // Current generation step
+	Total int    `json:"total,omitempty"` // Total generation steps
 }
 
 func (s *llmServer) Completion(ctx context.Context, req CompletionRequest, fn func(CompletionResponse)) error {

server/routes.go

@@ -51,7 +51,6 @@ import (
 	"github.com/ollama/ollama/types/model"
 	"github.com/ollama/ollama/version"
 	"github.com/ollama/ollama/x/imagegen"
-	imagegenapi "github.com/ollama/ollama/x/imagegen/api"
 )
 
 const signinURLStr = "https://ollama.com/connect?name=%s&key=%s"
@@ -164,29 +163,6 @@ func (s *Server) scheduleRunner(ctx context.Context, name string, caps []model.C
 	return runner.llama, model, &opts, nil
 }
 
-// ScheduleImageGenRunner schedules an image generation model runner.
-// This implements the imagegenapi.RunnerScheduler interface.
-func (s *Server) ScheduleImageGenRunner(c *gin.Context, modelName string, opts api.Options, keepAlive *api.Duration) (llm.LlamaServer, error) {
-	m := &Model{
-		Name:      modelName,
-		ShortName: modelName,
-		ModelPath: modelName, // For image gen, ModelPath is just the model name
-		Config: model.ConfigV2{
-			Capabilities: []string{"image"},
-		},
-	}
-
-	runnerCh, errCh := s.sched.GetRunner(c.Request.Context(), m, opts, keepAlive)
-	var runner *runnerRef
-	select {
-	case runner = <-runnerCh:
-	case err := <-errCh:
-		return nil, err
-	}
-
-	return runner.llama, nil
-}
-
 func signinURL() (string, error) {
 	pubKey, err := auth.GetPublicKey()
 	if err != nil {
@@ -214,12 +190,6 @@ func (s *Server) GenerateHandler(c *gin.Context) {
 		return
 	}
 
-	// Check if this is a known image generation model
-	if imagegen.ResolveModelName(req.Model) != "" {
-		imagegenapi.HandleGenerateRequest(c, s, req.Model, req.Prompt, req.KeepAlive, streamResponse)
-		return
-	}
-
 	name := model.ParseName(req.Model)
 	if !name.IsValid() {
 		// Ideally this is "invalid model name" but we're keeping with
@@ -1587,13 +1557,12 @@ func (s *Server) GenerateRoutes(rc *ollama.Registry) (http.Handler, error) {
 	r.GET("/v1/models", middleware.ListMiddleware(), s.ListHandler)
 	r.GET("/v1/models/:model", middleware.RetrieveMiddleware(), s.ShowHandler)
 	r.POST("/v1/responses", middleware.ResponsesMiddleware(), s.ChatHandler)
+	// Experimental OpenAI-compatible image generation endpoint
+	r.POST("/v1/images/generations", s.handleImageGeneration)
 
 	// Inference (Anthropic compatibility)
 	r.POST("/v1/messages", middleware.AnthropicMessagesMiddleware(), s.ChatHandler)
 
-	// Experimental image generation support
-	imagegenapi.RegisterRoutes(r, s)
-
 	if rc != nil {
 		// wrap old with new
 		rs := &registry.Local{
@@ -1911,6 +1880,62 @@ func toolCallId() string {
 	return "call_" + strings.ToLower(string(b))
 }
 
+func (s *Server) handleImageGeneration(c *gin.Context) {
+	var req struct {
+		Model  string `json:"model"`
+		Prompt string `json:"prompt"`
+		Size   string `json:"size"`
+	}
+	if err := c.ShouldBindJSON(&req); err != nil {
+		c.JSON(http.StatusBadRequest, gin.H{"error": err.Error()})
+		return
+	}
+
+	m, err := GetModel(req.Model)
+	if err != nil {
+		c.JSON(http.StatusNotFound, gin.H{"error": err.Error()})
+		return
+	}
+
+	runnerCh, errCh := s.sched.GetRunner(c.Request.Context(), m, api.Options{}, nil)
+	var runner *runnerRef
+	select {
+	case runner = <-runnerCh:
+	case err := <-errCh:
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	// Parse size (e.g., "1024x768") into width and height
+	width, height := int32(1024), int32(1024)
+	if req.Size != "" {
+		if _, err := fmt.Sscanf(req.Size, "%dx%d", &width, &height); err != nil {
+			c.JSON(http.StatusBadRequest, gin.H{"error": "invalid size format, expected WxH"})
+			return
+		}
+	}
+
+	var image []byte
+	err = runner.llama.Completion(c.Request.Context(), llm.CompletionRequest{
+		Prompt: req.Prompt,
+		Width:  width,
+		Height: height,
+	}, func(resp llm.CompletionResponse) {
+		if len(resp.Image) > 0 {
+			image = resp.Image
+		}
+	})
+	if err != nil {
+		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
+		return
+	}
+
+	c.JSON(http.StatusOK, gin.H{
+		"created": time.Now().Unix(),
+		"data":    []gin.H{{"b64_json": base64.StdEncoding.EncodeToString(image)}},
+	})
+}
+
 func (s *Server) ChatHandler(c *gin.Context) {
 	checkpointStart := time.Now()
 

server/sched_test.go

@@ -6,7 +6,6 @@ import (
 	"errors"
 	"log/slog"
 	"os"
-	"slices"
 	"testing"
 	"time"
 
@@ -17,7 +16,6 @@ import (
 	"github.com/ollama/ollama/fs/ggml"
 	"github.com/ollama/ollama/llm"
 	"github.com/ollama/ollama/ml"
-	"github.com/ollama/ollama/types/model"
 )
 
 func TestMain(m *testing.M) {
@@ -807,32 +805,8 @@ func (s *mockLlm) GetDeviceInfos(ctx context.Context) []ml.DeviceInfo { return n
 func (s *mockLlm) HasExited() bool                                    { return false }
 func (s *mockLlm) GetActiveDeviceIDs() []ml.DeviceID                  { return nil }
 
-// TestImageGenCapabilityDetection verifies that models with "image" capability
-// are correctly identified and routed differently from language models.
-func TestImageGenCapabilityDetection(t *testing.T) {
-	// Model with image capability should be detected
-	imageModel := &Model{
-		Config: model.ConfigV2{
-			Capabilities: []string{"image"},
-		},
-	}
-	require.True(t, slices.Contains(imageModel.Config.Capabilities, "image"))
-
-	// Model without image capability should not be detected
-	langModel := &Model{
-		Config: model.ConfigV2{
-			Capabilities: []string{"completion"},
-		},
-	}
-	require.False(t, slices.Contains(langModel.Config.Capabilities, "image"))
-
-	// Empty capabilities should not match
-	emptyModel := &Model{}
-	require.False(t, slices.Contains(emptyModel.Config.Capabilities, "image"))
-}
-
 // TestImageGenRunnerCanBeEvicted verifies that an image generation model
-// loaded in the scheduler can be evicted by a language model request.
+// loaded in the scheduler can be evicted when idle.
 func TestImageGenRunnerCanBeEvicted(t *testing.T) {
 	ctx, done := context.WithTimeout(t.Context(), 500*time.Millisecond)
 	defer done()
@@ -864,3 +838,59 @@ func TestImageGenRunnerCanBeEvicted(t *testing.T) {
 	require.NotNil(t, runner)
 	require.Equal(t, "/fake/image/model", runner.modelPath)
 }
+
+// TestImageGenSchedulerCoexistence verifies that image generation models
+// can coexist with language models in the scheduler and VRAM is tracked correctly.
+func TestImageGenSchedulerCoexistence(t *testing.T) {
+	ctx, done := context.WithTimeout(t.Context(), 500*time.Millisecond)
+	defer done()
+
+	s := InitScheduler(ctx)
+	s.getGpuFn = getGpuFn
+	s.getSystemInfoFn = getSystemInfoFn
+
+	// Load both an imagegen runner and a language model runner
+	imageGenRunner := &runnerRef{
+		model:           &Model{Name: "flux", ModelPath: "/fake/flux/model"},
+		modelPath:       "/fake/flux/model",
+		llama:           &mockLlm{vramSize: 8 * format.GigaByte, vramByGPU: map[ml.DeviceID]uint64{{Library: "Metal"}: 8 * format.GigaByte}},
+		sessionDuration: 10 * time.Millisecond,
+		numParallel:     1,
+		refCount:        0,
+	}
+
+	langModelRunner := &runnerRef{
+		model:           &Model{Name: "llama3", ModelPath: "/fake/llama3/model"},
+		modelPath:       "/fake/llama3/model",
+		llama:           &mockLlm{vramSize: 4 * format.GigaByte, vramByGPU: map[ml.DeviceID]uint64{{Library: "Metal"}: 4 * format.GigaByte}},
+		sessionDuration: 10 * time.Millisecond,
+		numParallel:     1,
+		refCount:        0,
+	}
+
+	s.loadedMu.Lock()
+	s.loaded["/fake/flux/model"] = imageGenRunner
+	s.loaded["/fake/llama3/model"] = langModelRunner
+	s.loadedMu.Unlock()
+
+	// Verify both are loaded
+	s.loadedMu.Lock()
+	require.Len(t, s.loaded, 2)
+	require.NotNil(t, s.loaded["/fake/flux/model"])
+	require.NotNil(t, s.loaded["/fake/llama3/model"])
+	s.loadedMu.Unlock()
+
+	// Verify updateFreeSpace accounts for both
+	gpus := []ml.DeviceInfo{
+		{
+			DeviceID:    ml.DeviceID{Library: "Metal"},
+			TotalMemory: 24 * format.GigaByte,
+			FreeMemory:  24 * format.GigaByte,
+		},
+	}
+	s.updateFreeSpace(gpus)
+
+	// Free memory should be reduced by both models
+	expectedFree := uint64(24*format.GigaByte) - uint64(8*format.GigaByte) - uint64(4*format.GigaByte)
+	require.Equal(t, expectedFree, gpus[0].FreeMemory)
+}

x/imagegen/api/handler.go

@@ -1,231 +0,0 @@
-package api
-
-import (
-	"fmt"
-	"net/http"
-	"strconv"
-	"strings"
-	"time"
-
-	"github.com/gin-gonic/gin"
-
-	"github.com/ollama/ollama/api"
-	"github.com/ollama/ollama/llm"
-	"github.com/ollama/ollama/x/imagegen"
-)
-
-// RunnerScheduler is the interface for scheduling a model runner.
-// This is implemented by server.Server to avoid circular imports.
-type RunnerScheduler interface {
-	ScheduleImageGenRunner(ctx *gin.Context, modelName string, opts api.Options, keepAlive *api.Duration) (llm.LlamaServer, error)
-}
-
-// RegisterRoutes registers the image generation API routes.
-func RegisterRoutes(r gin.IRouter, scheduler RunnerScheduler) {
-	r.POST("/v1/images/generations", func(c *gin.Context) {
-		ImageGenerationHandler(c, scheduler)
-	})
-}
-
-// ImageGenerationHandler handles OpenAI-compatible image generation requests.
-func ImageGenerationHandler(c *gin.Context, scheduler RunnerScheduler) {
-	var req ImageGenerationRequest
-	if err := c.BindJSON(&req); err != nil {
-		c.JSON(http.StatusBadRequest, gin.H{"error": gin.H{"message": err.Error()}})
-		return
-	}
-
-	// Validate required fields
-	if req.Model == "" {
-		c.JSON(http.StatusBadRequest, gin.H{"error": gin.H{"message": "model is required"}})
-		return
-	}
-	if req.Prompt == "" {
-		c.JSON(http.StatusBadRequest, gin.H{"error": gin.H{"message": "prompt is required"}})
-		return
-	}
-
-	// Apply defaults
-	if req.N == 0 {
-		req.N = 1
-	}
-	if req.Size == "" {
-		req.Size = "1024x1024"
-	}
-	if req.ResponseFormat == "" {
-		req.ResponseFormat = "b64_json"
-	}
-
-	// Verify model exists
-	if imagegen.ResolveModelName(req.Model) == "" {
-		c.JSON(http.StatusNotFound, gin.H{"error": gin.H{"message": fmt.Sprintf("model %q not found", req.Model)}})
-		return
-	}
-
-	// Parse size
-	width, height := parseSize(req.Size)
-
-	// Build options - we repurpose NumCtx/NumGPU for width/height
-	opts := api.Options{}
-	opts.NumCtx = int(width)
-	opts.NumGPU = int(height)
-
-	// Schedule runner
-	runner, err := scheduler.ScheduleImageGenRunner(c, req.Model, opts, nil)
-	if err != nil {
-		status := http.StatusInternalServerError
-		if strings.Contains(err.Error(), "not found") {
-			status = http.StatusNotFound
-		}
-		c.JSON(status, gin.H{"error": gin.H{"message": err.Error()}})
-		return
-	}
-
-	// Build completion request
-	completionReq := llm.CompletionRequest{
-		Prompt:  req.Prompt,
-		Options: &opts,
-	}
-
-	if req.Stream {
-		handleStreamingResponse(c, runner, completionReq, req.ResponseFormat)
-	} else {
-		handleNonStreamingResponse(c, runner, completionReq, req.ResponseFormat)
-	}
-}
-
-func handleStreamingResponse(c *gin.Context, runner llm.LlamaServer, req llm.CompletionRequest, format string) {
-	c.Header("Content-Type", "text/event-stream")
-	c.Header("Cache-Control", "no-cache")
-	c.Header("Connection", "keep-alive")
-
-	var imageBase64 string
-	err := runner.Completion(c.Request.Context(), req, func(resp llm.CompletionResponse) {
-		if resp.Done {
-			imageBase64 = extractBase64(resp.Content)
-		} else {
-			progress := parseProgress(resp.Content)
-			if progress.Total > 0 {
-				c.SSEvent("progress", progress)
-				c.Writer.Flush()
-			}
-		}
-	})
-	if err != nil {
-		c.SSEvent("error", gin.H{"error": err.Error()})
-		return
-	}
-
-	c.SSEvent("done", buildResponse(imageBase64, format))
-}
-
-func handleNonStreamingResponse(c *gin.Context, runner llm.LlamaServer, req llm.CompletionRequest, format string) {
-	var imageBase64 string
-	err := runner.Completion(c.Request.Context(), req, func(resp llm.CompletionResponse) {
-		if resp.Done {
-			imageBase64 = extractBase64(resp.Content)
-		}
-	})
-	if err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"error": gin.H{"message": err.Error()}})
-		return
-	}
-
-	c.JSON(http.StatusOK, buildResponse(imageBase64, format))
-}
-
-func parseSize(size string) (int32, int32) {
-	parts := strings.Split(size, "x")
-	if len(parts) != 2 {
-		return 1024, 1024
-	}
-	w, _ := strconv.Atoi(parts[0])
-	h, _ := strconv.Atoi(parts[1])
-	if w == 0 {
-		w = 1024
-	}
-	if h == 0 {
-		h = 1024
-	}
-	return int32(w), int32(h)
-}
-
-func extractBase64(content string) string {
-	if strings.HasPrefix(content, "IMAGE_BASE64:") {
-		return content[13:]
-	}
-	return ""
-}
-
-func parseProgress(content string) ImageProgressEvent {
-	var step, total int
-	fmt.Sscanf(content, "\rGenerating: step %d/%d", &step, &total)
-	return ImageProgressEvent{Step: step, Total: total}
-}
-
-func buildResponse(imageBase64, format string) ImageGenerationResponse {
-	resp := ImageGenerationResponse{
-		Created: time.Now().Unix(),
-		Data:    make([]ImageData, 1),
-	}
-
-	if imageBase64 == "" {
-		return resp
-	}
-
-	if format == "url" {
-		// URL format not supported when using base64 transfer
-		resp.Data[0].B64JSON = imageBase64
-	} else {
-		resp.Data[0].B64JSON = imageBase64
-	}
-
-	return resp
-}
-
-// HandleGenerateRequest handles Ollama /api/generate requests for image gen models.
-// This allows routes.go to delegate image generation with minimal code.
-func HandleGenerateRequest(c *gin.Context, scheduler RunnerScheduler, modelName, prompt string, keepAlive *api.Duration, streamFn func(c *gin.Context, ch chan any)) {
-	opts := api.Options{}
-
-	// Schedule runner
-	runner, err := scheduler.ScheduleImageGenRunner(c, modelName, opts, keepAlive)
-	if err != nil {
-		c.JSON(http.StatusInternalServerError, gin.H{"error": err.Error()})
-		return
-	}
-
-	// Build completion request
-	completionReq := llm.CompletionRequest{
-		Prompt:  prompt,
-		Options: &opts,
-	}
-
-	// Stream responses via channel
-	ch := make(chan any)
-	go func() {
-		defer close(ch)
-		err := runner.Completion(c.Request.Context(), completionReq, func(resp llm.CompletionResponse) {
-			ch <- GenerateResponse{
-				Model:     modelName,
-				CreatedAt: time.Now().UTC(),
-				Response:  resp.Content,
-				Done:      resp.Done,
-			}
-		})
-		if err != nil {
-			// Log error but don't block - channel is already being consumed
-			_ = err
-		}
-	}()
-
-	streamFn(c, ch)
-}
-
-// GenerateResponse matches api.GenerateResponse structure for streaming.
-type GenerateResponse struct {
-	Model     string    `json:"model"`
-	CreatedAt time.Time `json:"created_at"`
-	Response  string    `json:"response"`
-	Done      bool      `json:"done"`
-}

x/imagegen/api/types.go

@@ -1,31 +0,0 @@
-// Package api provides OpenAI-compatible image generation API types.
-package api
-
-// ImageGenerationRequest is an OpenAI-compatible image generation request.
-type ImageGenerationRequest struct {
-	Model          string `json:"model"`
-	Prompt         string `json:"prompt"`
-	N              int    `json:"n,omitempty"`
-	Size           string `json:"size,omitempty"`
-	ResponseFormat string `json:"response_format,omitempty"`
-	Stream         bool   `json:"stream,omitempty"`
-}
-
-// ImageGenerationResponse is an OpenAI-compatible image generation response.
-type ImageGenerationResponse struct {
-	Created int64       `json:"created"`
-	Data    []ImageData `json:"data"`
-}
-
-// ImageData contains the generated image data.
-type ImageData struct {
-	URL           string `json:"url,omitempty"`
-	B64JSON       string `json:"b64_json,omitempty"`
-	RevisedPrompt string `json:"revised_prompt,omitempty"`
-}
-
-// ImageProgressEvent is sent during streaming to indicate generation progress.
-type ImageProgressEvent struct {
-	Step  int `json:"step"`
-	Total int `json:"total"`
-}

x/imagegen/cli.go

@@ -7,7 +7,6 @@ package imagegen
 
 import (
 	"encoding/base64"
-	"encoding/json"
 	"errors"
 	"fmt"
 	"io"
@@ -39,77 +38,17 @@ func DefaultOptions() ImageGenOptions {
 	return ImageGenOptions{
 		Width:  1024,
 		Height: 1024,
-		Steps:  9,
+		Steps:  0, // 0 means model default
 		Seed:   0, // 0 means random
 	}
 }
 
-// ModelInfo contains metadata about an image generation model.
-type ModelInfo struct {
-	Architecture   string
-	ParameterCount int64
-	Quantization   string
-}
-
-// GetModelInfo returns metadata about an image generation model.
-func GetModelInfo(modelName string) (*ModelInfo, error) {
-	manifest, err := LoadManifest(modelName)
-	if err != nil {
-		return nil, fmt.Errorf("failed to load manifest: %w", err)
-	}
-
-	info := &ModelInfo{}
-
-	// Read model_index.json for architecture, parameter count, and quantization
-	if data, err := manifest.ReadConfig("model_index.json"); err == nil {
-		var index struct {
-			Architecture   string `json:"architecture"`
-			ParameterCount int64  `json:"parameter_count"`
-			Quantization   string `json:"quantization"`
-		}
-		if json.Unmarshal(data, &index) == nil {
-			info.Architecture = index.Architecture
-			info.ParameterCount = index.ParameterCount
-			info.Quantization = index.Quantization
-		}
-	}
-
-	// Fallback: detect quantization from tensor names if not in config
-	if info.Quantization == "" {
-		for _, layer := range manifest.Manifest.Layers {
-			if strings.HasSuffix(layer.Name, ".weight_scale") {
-				info.Quantization = "FP8"
-				break
-			}
-		}
-		if info.Quantization == "" {
-			info.Quantization = "BF16"
-		}
-	}
-
-	// Fallback: estimate parameter count if not in config
-	if info.ParameterCount == 0 {
-		var totalSize int64
-		for _, layer := range manifest.Manifest.Layers {
-			if layer.MediaType == "application/vnd.ollama.image.tensor" {
-				if !strings.HasSuffix(layer.Name, "_scale") && !strings.HasSuffix(layer.Name, "_qbias") {
-					totalSize += layer.Size
-				}
-			}
-		}
-		// Assume BF16 (2 bytes/param) as rough estimate
-		info.ParameterCount = totalSize / 2
-	}
-
-	return info, nil
-}
-
 // RegisterFlags adds image generation flags to the given command.
 // Flags are hidden since they only apply to image generation models.
 func RegisterFlags(cmd *cobra.Command) {
 	cmd.Flags().Int("width", 1024, "Image width")
 	cmd.Flags().Int("height", 1024, "Image height")
-	cmd.Flags().Int("steps", 9, "Denoising steps")
+	cmd.Flags().Int("steps", 0, "Denoising steps (0 = model default)")
 	cmd.Flags().Int("seed", 0, "Random seed (0 for random)")
 	cmd.Flags().String("negative", "", "Negative prompt")
 	cmd.Flags().MarkHidden("width")
@@ -152,23 +91,18 @@ func RunCLI(cmd *cobra.Command, name string, prompt string, interactive bool, ke
 }
 
 // generateImageWithOptions generates an image with the given options.
-func generateImageWithOptions(cmd *cobra.Command, modelName, prompt string, keepAlive *api.Duration, opts ImageGenOptions) error {
+// Note: opts are currently unused as the native API doesn't support size parameters.
+// Use OpenAI-compatible endpoint (/v1/images/generations) for dimension control.
+func generateImageWithOptions(cmd *cobra.Command, modelName, prompt string, keepAlive *api.Duration, _ ImageGenOptions) error {
 	client, err := api.ClientFromEnvironment()
 	if err != nil {
 		return err
 	}
 
-	// Build request with image gen options encoded in Options fields
-	// NumCtx=width, NumGPU=height, NumPredict=steps, Seed=seed
 	req := &api.GenerateRequest{
 		Model:  modelName,
 		Prompt: prompt,
-		Options: map[string]any{
-			"num_ctx":     opts.Width,
-			"num_gpu":     opts.Height,
-			"num_predict": opts.Steps,
-			"seed":        opts.Seed,
-		},
+		// Note: Size is only available via OpenAI-compatible /v1/images/generations endpoint
 	}
 	if keepAlive != nil {
 		req.KeepAlive = keepAlive

x/imagegen/cmd/engine/main.go

@@ -12,6 +12,7 @@ import (
 	"path/filepath"
 	"runtime/pprof"
 
+	"github.com/ollama/ollama/x/imagegen"
 	"github.com/ollama/ollama/x/imagegen/mlx"
 	"github.com/ollama/ollama/x/imagegen/models/gemma3"
 	"github.com/ollama/ollama/x/imagegen/models/gpt_oss"
@@ -48,7 +49,7 @@ func main() {
 	// Image generation params
 	width := flag.Int("width", 1024, "Image width")
 	height := flag.Int("height", 1024, "Image height")
-	steps := flag.Int("steps", 9, "Denoising steps")
+	steps := flag.Int("steps", 0, "Denoising steps (0 = model default)")
 	seed := flag.Int64("seed", 42, "Random seed")
 	out := flag.String("output", "output.png", "Output path")
 

x/imagegen/manifest.go

@@ -175,3 +175,63 @@ func (m *ModelManifest) HasTensorLayers() bool {
 	}
 	return false
 }
+
+// ModelInfo contains metadata about an image generation model.
+type ModelInfo struct {
+	Architecture   string
+	ParameterCount int64
+	Quantization   string
+}
+
+// GetModelInfo returns metadata about an image generation model.
+func GetModelInfo(modelName string) (*ModelInfo, error) {
+	manifest, err := LoadManifest(modelName)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load manifest: %w", err)
+	}
+
+	info := &ModelInfo{}
+
+	// Read model_index.json for architecture, parameter count, and quantization
+	if data, err := manifest.ReadConfig("model_index.json"); err == nil {
+		var index struct {
+			Architecture   string `json:"architecture"`
+			ParameterCount int64  `json:"parameter_count"`
+			Quantization   string `json:"quantization"`
+		}
+		if json.Unmarshal(data, &index) == nil {
+			info.Architecture = index.Architecture
+			info.ParameterCount = index.ParameterCount
+			info.Quantization = index.Quantization
+		}
+	}
+
+	// Fallback: detect quantization from tensor names if not in config
+	if info.Quantization == "" {
+		for _, layer := range manifest.Manifest.Layers {
+			if strings.HasSuffix(layer.Name, ".weight_scale") {
+				info.Quantization = "FP8"
+				break
+			}
+		}
+		if info.Quantization == "" {
+			info.Quantization = "BF16"
+		}
+	}
+
+	// Fallback: estimate parameter count if not in config
+	if info.ParameterCount == 0 {
+		var totalSize int64
+		for _, layer := range manifest.Manifest.Layers {
+			if layer.MediaType == "application/vnd.ollama.image.tensor" {
+				if !strings.HasSuffix(layer.Name, "_scale") && !strings.HasSuffix(layer.Name, "_qbias") {
+					totalSize += layer.Size
+				}
+			}
+		}
+		// Assume BF16 (2 bytes/param) as rough estimate
+		info.ParameterCount = totalSize / 2
+	}
+
+	return info, nil
+}

x/imagegen/memory.go

@@ -95,8 +95,3 @@ func EstimateVRAM(modelName string) uint64 {
 	}
 	return 21 * GB
 }
-
-// HasTensorLayers checks if the given model has tensor layers.
-func HasTensorLayers(modelName string) bool {
-	return ResolveModelName(modelName) != ""
-}

x/imagegen/memory_test.go

@@ -94,13 +94,6 @@ func TestEstimateVRAMDefault(t *testing.T) {
 	}
 }
 
-func TestHasTensorLayers(t *testing.T) {
-	// Non-existent model should return false
-	if HasTensorLayers("nonexistent-model") {
-		t.Error("HasTensorLayers() should return false for non-existent model")
-	}
-}
-
 func TestResolveModelName(t *testing.T) {
 	// Non-existent model should return empty string
 	result := ResolveModelName("nonexistent-model")

x/imagegen/models/qwen_image/qwen_image.go

@@ -9,6 +9,7 @@ import (
 	"path/filepath"
 	"time"
 
+	"github.com/ollama/ollama/x/imagegen"
 	"github.com/ollama/ollama/x/imagegen/cache"
 	"github.com/ollama/ollama/x/imagegen/mlx"
 	"github.com/ollama/ollama/x/imagegen/tokenizer"
@@ -172,7 +173,7 @@ func (m *Model) generate(cfg *GenerateConfig) (*mlx.Array, error) {
 		cfg.Height = 1024
 	}
 	if cfg.Steps <= 0 {
-		cfg.Steps = 30
+		cfg.Steps = 50
 	}
 	if cfg.CFGScale <= 0 {
 		cfg.CFGScale = 4.0

x/imagegen/models/zimage/zimage.go

@@ -194,7 +194,7 @@ func (m *Model) generate(ctx context.Context, cfg *GenerateConfig) (*mlx.Array,
 		cfg.Height = 1024
 	}
 	if cfg.Steps <= 0 {
-		cfg.Steps = 9 // Turbo default
+		cfg.Steps = 9 // Z-Image turbo default
 	}
 	if cfg.CFGScale <= 0 {
 		cfg.CFGScale = 4.0

x/imagegen/runner/runner.go

@@ -136,16 +136,8 @@ func (s *Server) completionHandler(w http.ResponseWriter, r *http.Request) {
 	s.mu.Lock()
 	defer s.mu.Unlock()
 
-	// Apply defaults
-	if req.Width <= 0 {
-		req.Width = 1024
-	}
-	if req.Height <= 0 {
-		req.Height = 1024
-	}
-	if req.Steps <= 0 {
-		req.Steps = 9
-	}
+	// Model applies its own defaults for width/height/steps
+	// Only seed needs to be set here if not provided
 	if req.Seed <= 0 {
 		req.Seed = time.Now().UnixNano()
 	}

x/imagegen/server.go

@@ -4,6 +4,7 @@ import (
 	"bufio"
 	"bytes"
 	"context"
+	"encoding/base64"
 	"encoding/json"
 	"errors"
 	"fmt"
@@ -25,6 +26,11 @@ import (
 )
 
 // Server wraps an image generation subprocess to implement llm.LlamaServer.
+//
+// This implementation is compatible with Ollama's scheduler and can be loaded/unloaded
+// like any other model. The plan is to eventually bring this into the llm/ package
+// and evolve llm/ to support MLX and multimodal models. For now, keeping the code
+// separate allows for independent iteration on image generation support.
 type Server struct {
 	mu          sync.Mutex
 	cmd         *exec.Cmd
@@ -37,22 +43,6 @@ type Server struct {
 	lastErrLock sync.Mutex
 }
 
-// completionRequest is sent to the subprocess
-type completionRequest struct {
-	Prompt string `json:"prompt"`
-	Width  int32  `json:"width,omitempty"`
-	Height int32  `json:"height,omitempty"`
-	Steps  int    `json:"steps,omitempty"`
-	Seed   int64  `json:"seed,omitempty"`
-}
-
-// completionResponse is received from the subprocess
-type completionResponse struct {
-	Content string `json:"content,omitempty"`
-	Image   string `json:"image,omitempty"`
-	Done    bool   `json:"done"`
-}
-
 // NewServer spawns a new image generation subprocess and waits until it's ready.
 func NewServer(modelName string) (*Server, error) {
 	// Validate platform support before attempting to start
@@ -139,7 +129,6 @@ func NewServer(modelName string) (*Server, error) {
 		for scanner.Scan() {
 			line := scanner.Text()
 			slog.Warn("image-runner", "msg", line)
-			// Capture last error line for better error reporting
 			s.lastErrLock.Lock()
 			s.lastErr = line
 			s.lastErrLock.Unlock()
@@ -171,7 +160,6 @@ func (s *Server) ModelPath() string {
 	return s.modelName
 }
 
-// Load is called by the scheduler after the server is created.
 func (s *Server) Load(ctx context.Context, systemInfo ml.SystemInfo, gpus []ml.DeviceInfo, requireFull bool) ([]ml.DeviceID, error) {
 	return nil, nil
 }
@@ -204,20 +192,16 @@ func (s *Server) waitUntilRunning() error {
 	for {
 		select {
 		case err := <-s.done:
-			// Include last stderr line for better error context
-			s.lastErrLock.Lock()
-			lastErr := s.lastErr
-			s.lastErrLock.Unlock()
-			if lastErr != "" {
-				return fmt.Errorf("image runner failed: %s (exit: %v)", lastErr, err)
+			// Include recent stderr lines for better error context
+			errMsg := s.getLastErr()
+			if errMsg != "" {
+				return fmt.Errorf("image runner failed: %s (exit: %v)", errMsg, err)
 			}
 			return fmt.Errorf("image runner exited unexpectedly: %w", err)
 		case <-timeout:
-			s.lastErrLock.Lock()
-			lastErr := s.lastErr
-			s.lastErrLock.Unlock()
-			if lastErr != "" {
-				return fmt.Errorf("timeout waiting for image runner: %s", lastErr)
+			errMsg := s.getLastErr()
+			if errMsg != "" {
+				return fmt.Errorf("timeout waiting for image runner: %s", errMsg)
 			}
 			return errors.New("timeout waiting for image runner to start")
 		case <-ticker.C:
@@ -229,44 +213,39 @@ func (s *Server) waitUntilRunning() error {
 	}
 }
 
-// WaitUntilRunning implements the LlamaServer interface (no-op since NewServer waits).
-func (s *Server) WaitUntilRunning(ctx context.Context) error {
-	return nil
+// getLastErr returns the last stderr line.
+func (s *Server) getLastErr() string {
+	s.lastErrLock.Lock()
+	defer s.lastErrLock.Unlock()
+	return s.lastErr
 }
 
-// Completion generates an image from the prompt via the subprocess.
+func (s *Server) WaitUntilRunning(ctx context.Context) error { return nil }
+
 func (s *Server) Completion(ctx context.Context, req llm.CompletionRequest, fn func(llm.CompletionResponse)) error {
-	// Build request
-	creq := completionRequest{
+	seed := req.Seed
+	if seed == 0 {
+		seed = time.Now().UnixNano()
+	}
+
+	// Build request for subprocess
+	creq := struct {
+		Prompt string `json:"prompt"`
+		Width  int32  `json:"width,omitempty"`
+		Height int32  `json:"height,omitempty"`
+		Seed   int64  `json:"seed,omitempty"`
+	}{
 		Prompt: req.Prompt,
-		Width:  1024,
-		Height: 1024,
-		Steps:  9,
-		Seed:   time.Now().UnixNano(),
+		Width:  req.Width,
+		Height: req.Height,
+		Seed:   seed,
 	}
 
-	if req.Options != nil {
-		if req.Options.NumCtx > 0 && req.Options.NumCtx <= 4096 {
-			creq.Width = int32(req.Options.NumCtx)
-		}
-		if req.Options.NumGPU > 0 && req.Options.NumGPU <= 4096 {
-			creq.Height = int32(req.Options.NumGPU)
-		}
-		if req.Options.NumPredict > 0 && req.Options.NumPredict <= 100 {
-			creq.Steps = req.Options.NumPredict
-		}
-		if req.Options.Seed > 0 {
-			creq.Seed = int64(req.Options.Seed)
-		}
-	}
-
-	// Encode request body
 	body, err := json.Marshal(creq)
 	if err != nil {
 		return err
 	}
 
-	// Send request to subprocess
 	url := fmt.Sprintf("http://127.0.0.1:%d/completion", s.port)
 	httpReq, err := http.NewRequestWithContext(ctx, "POST", url, bytes.NewReader(body))
 	if err != nil {
@@ -281,30 +260,40 @@ func (s *Server) Completion(ctx context.Context, req llm.CompletionRequest, fn f
 	defer resp.Body.Close()
 
 	if resp.StatusCode != http.StatusOK {
-		return fmt.Errorf("completion request failed: %d", resp.StatusCode)
+		return fmt.Errorf("request failed: %d", resp.StatusCode)
 	}
 
-	// Stream responses - use large buffer for base64 image data
 	scanner := bufio.NewScanner(resp.Body)
 	scanner.Buffer(make([]byte, 1024*1024), 16*1024*1024) // 16MB max
 	for scanner.Scan() {
-		var cresp completionResponse
-		if err := json.Unmarshal(scanner.Bytes(), &cresp); err != nil {
+		// Parse subprocess response (has singular "image" field)
+		var raw struct {
+			Image   string `json:"image,omitempty"`
+			Content string `json:"content,omitempty"`
+			Done    bool   `json:"done"`
+			Step    int    `json:"step,omitempty"`
+			Total   int    `json:"total,omitempty"`
+		}
+		if err := json.Unmarshal(scanner.Bytes(), &raw); err != nil {
 			continue
 		}
 
-		content := cresp.Content
-		// If this is the final response with an image, encode it in the content
-		if cresp.Done && cresp.Image != "" {
-			content = "IMAGE_BASE64:" + cresp.Image
+		// Convert to llm.CompletionResponse
+		cresp := llm.CompletionResponse{
+			Content: raw.Content,
+			Done:    raw.Done,
+			Step:    raw.Step,
+			Total:   raw.Total,
+		}
+		if raw.Image != "" {
+			if data, err := base64.StdEncoding.DecodeString(raw.Image); err == nil {
+				cresp.Image = data
+			}
 		}
 
-		fn(llm.CompletionResponse{
-			Content: content,
-			Done:    cresp.Done,
-		})
+		fn(cresp)
 		if cresp.Done {
-			break
+			return nil
 		}
 	}
 
@@ -346,22 +335,18 @@ func (s *Server) VRAMByGPU(id ml.DeviceID) uint64 {
 	return s.vramSize
 }
 
-// Embedding is not supported for image generation models.
 func (s *Server) Embedding(ctx context.Context, input string) ([]float32, int, error) {
-	return nil, 0, errors.New("embedding not supported for image generation models")
+	return nil, 0, errors.New("not supported")
 }
 
-// Tokenize is not supported for image generation models.
 func (s *Server) Tokenize(ctx context.Context, content string) ([]int, error) {
-	return nil, errors.New("tokenize not supported for image generation models")
+	return nil, errors.New("not supported")
 }
 
-// Detokenize is not supported for image generation models.
 func (s *Server) Detokenize(ctx context.Context, tokens []int) (string, error) {
-	return "", errors.New("detokenize not supported for image generation models")
+	return "", errors.New("not supported")
 }
 
-// Pid returns the subprocess PID.
 func (s *Server) Pid() int {
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -371,17 +356,9 @@ func (s *Server) Pid() int {
 	return -1
 }
 
-// GetPort returns the subprocess port.
-func (s *Server) GetPort() int {
-	return s.port
-}
+func (s *Server) GetPort() int                                       { return s.port }
+func (s *Server) GetDeviceInfos(ctx context.Context) []ml.DeviceInfo { return nil }
 
-// GetDeviceInfos returns nil since we don't track GPU info.
-func (s *Server) GetDeviceInfos(ctx context.Context) []ml.DeviceInfo {
-	return nil
-}
-
-// HasExited returns true if the subprocess has exited.
 func (s *Server) HasExited() bool {
 	select {
 	case <-s.done: