diff --git a/backend/internal/service/grok_media.go b/backend/internal/service/grok_media.go
index 07e8c57bc1..fb05b64b01 100644
--- a/backend/internal/service/grok_media.go
+++ b/backend/internal/service/grok_media.go
@@ -292,6 +292,11 @@ func (s *OpenAIGatewayService) ForwardGrokMedia(
 		return nil, err
 	}
 
+	body, contentType, err = prepareGrokMediaForwardBody(endpoint, body, contentType)
+	if err != nil {
+		return nil, err
+	}
+
 	var bodyReader io.Reader
 	if endpoint.RequiresRequestBody() {
 		bodyReader = bytes.NewReader(body)
@@ -356,6 +361,69 @@ func (s *OpenAIGatewayService) ForwardGrokMedia(
 	}, nil
 }
 
+func prepareGrokMediaForwardBody(endpoint GrokMediaEndpoint, body []byte, contentType string) ([]byte, string, error) {
+	if endpoint != GrokMediaEndpointImagesEdits || gjson.ValidBytes(body) {
+		return body, contentType, nil
+	}
+	mediaType, _, err := mime.ParseMediaType(strings.TrimSpace(contentType))
+	if err != nil || !strings.EqualFold(mediaType, "multipart/form-data") {
+		return body, contentType, nil
+	}
+
+	info := ParseGrokMediaRequest(contentType, body)
+	payload := make(map[string]any)
+	if info.Model != "" {
+		payload["model"] = info.Model
+	}
+	if info.Prompt != "" {
+		payload["prompt"] = info.Prompt
+	}
+	if info.N > 1 {
+		payload["n"] = info.N
+	}
+	if info.Size != "" {
+		payload["size"] = info.Size
+	}
+
+	images := make([]map[string]string, 0, len(info.InputImageURLs)+len(info.Uploads))
+	for _, imageURL := range info.InputImageURLs {
+		if imageURL = strings.TrimSpace(imageURL); imageURL != "" {
+			images = append(images, map[string]string{"image_url": imageURL})
+		}
+	}
+	for _, upload := range info.Uploads {
+		dataURL, err := openAIImageUploadToDataURL(upload)
+		if err != nil {
+			return nil, "", err
+		}
+		images = append(images, map[string]string{"image_url": dataURL})
+	}
+	if len(images) > 0 {
+		payload["image"] = images[0]
+		if len(images) > 1 {
+			payload["images"] = images
+		}
+	}
+
+	maskImageURL := strings.TrimSpace(info.MaskImageURL)
+	if info.MaskUpload != nil {
+		dataURL, err := openAIImageUploadToDataURL(*info.MaskUpload)
+		if err != nil {
+			return nil, "", err
+		}
+		maskImageURL = dataURL
+	}
+	if maskImageURL != "" {
+		payload["mask"] = map[string]string{"image_url": maskImageURL}
+	}
+
+	out, err := marshalOpenAIUpstreamJSON(payload)
+	if err != nil {
+		return nil, "", err
+	}
+	return out, "application/json", nil
+}
+
 type grokMediaUsageMetadata struct {
 	ResponseID       string
 	Usage            OpenAIUsage
diff --git a/backend/internal/service/openai_gateway_grok_test.go b/backend/internal/service/openai_gateway_grok_test.go
index a095243f57..ad088be725 100644
--- a/backend/internal/service/openai_gateway_grok_test.go
+++ b/backend/internal/service/openai_gateway_grok_test.go
@@ -229,6 +229,58 @@ func TestForwardGrokMediaImagesGenerationPassthrough(t *testing.T) {
 	require.Equal(t, ImageBillingSize2K, result.ImageSize)
 }
 
+func TestForwardGrokMediaImagesEditMultipartConvertsToJSON(t *testing.T) {
+	t.Setenv(xai.EnvAllowUnsafeURLOverrides, "true")
+	gin.SetMode(gin.TestMode)
+
+	var buf bytes.Buffer
+	writer := multipart.NewWriter(&buf)
+	require.NoError(t, writer.WriteField("model", "grok-imagine-edit"))
+	require.NoError(t, writer.WriteField("prompt", "edit this private image"))
+	partHeader := textproto.MIMEHeader{}
+	partHeader.Set("Content-Disposition", `form-data; name="image"; filename="input.png"`)
+	partHeader.Set("Content-Type", "image/png")
+	part, err := writer.CreatePart(partHeader)
+	require.NoError(t, err)
+	_, err = part.Write([]byte{0x89, 0x50, 0x4e, 0x47, 0x0d, 0x0a, 0x1a, 0x0a})
+	require.NoError(t, err)
+	require.NoError(t, writer.Close())
+
+	recorder := httptest.NewRecorder()
+	c, _ := gin.CreateTestContext(recorder)
+	c.Request = httptest.NewRequest(http.MethodPost, "/v1/images/edits", bytes.NewReader(buf.Bytes()))
+	c.Request.Header.Set("Content-Type", writer.FormDataContentType())
+
+	account := &Account{
+		ID:          62,
+		Name:        "grok",
+		Platform:    PlatformGrok,
+		Type:        AccountTypeAPIKey,
+		Concurrency: 1,
+		Credentials: map[string]any{
+			"api_key":  "api-key",
+			"base_url": "https://xai.test/v1",
+		},
+	}
+	upstream := &httpUpstreamRecorder{resp: &http.Response{
+		StatusCode: http.StatusOK,
+		Header: http.Header{
+			"Content-Type": []string{"application/json"},
+		},
+		Body: io.NopCloser(strings.NewReader(`{"data":[]}`)),
+	}}
+	svc := &OpenAIGatewayService{httpUpstream: upstream}
+
+	_, err = svc.ForwardGrokMedia(context.Background(), c, account, GrokMediaEndpointImagesEdits, "", buf.Bytes(), writer.FormDataContentType())
+	require.NoError(t, err)
+	require.Equal(t, "https://xai.test/v1/images/edits", upstream.lastReq.URL.String())
+	require.Equal(t, "application/json", upstream.lastReq.Header.Get("Content-Type"))
+	require.True(t, json.Valid(upstream.lastBody))
+	require.Equal(t, "grok-imagine-edit", gjson.GetBytes(upstream.lastBody, "model").String())
+	require.Equal(t, "edit this private image", gjson.GetBytes(upstream.lastBody, "prompt").String())
+	require.True(t, strings.HasPrefix(gjson.GetBytes(upstream.lastBody, "image.image_url").String(), "data:image/png;base64,"))
+}
+
 func TestForwardGrokMediaVideoGenerationReturnsUsageAndResponseID(t *testing.T) {
 	t.Setenv(xai.EnvAllowUnsafeURLOverrides, "true")
 	gin.SetMode(gin.TestMode)