fix(aihubmix): gemini image generation (#9601)

src/renderer/src/aiCore/clients/gemini/GeminiAPIClient.ts

@@ -429,8 +429,7 @@ export class GeminiAPIClient extends BaseApiClient<
   private getGenerateImageParameter(): Partial<GenerateContentConfig> {
     return {
       systemInstruction: undefined,
-      responseModalities: [Modality.TEXT, Modality.IMAGE],
-      responseMimeType: 'text/plain'
+      responseModalities: [Modality.TEXT, Modality.IMAGE]
     }
   }
 

src/renderer/src/config/models.ts

@@ -2471,6 +2471,7 @@ export const SUPPORTED_DISABLE_GENERATION_MODELS = [
 export const GENERATE_IMAGE_MODELS = [
   'gemini-2.0-flash-exp-image-generation',
   'gemini-2.0-flash-preview-image-generation',
+  'gemini-2.5-flash-image-preview',
   'grok-2-image-1212',
   'grok-2-image',
   'grok-2-image-latest',