diff --git a/src/volces/image.ts b/src/volces/image.ts
index 4a4d838..58d802c 100644
--- a/src/volces/image.ts
+++ b/src/volces/image.ts
@@ -1,3 +1,11 @@
+export const models = [
+  'doubao-seedream-4-0-250828',
+  'doubao-seedream-3-0-t2i-250415',
+  'doubao-seededit-3-0-i2i-250628'
+] as const;
+
+export type VolcesImageModel = (typeof models)[number];
+
 export class VolcesImage {
   apiUrl = 'https://ark.cn-beijing.volces.com/api/v3/images/generations';
   apiKey: string;
@@ -7,6 +15,27 @@ export class VolcesImage {
   }
 
   async generateImage(data: VolcesImageRequest): Promise<VolcesImageResponse> {
+    if (!data.model) {
+      data.model = models[0]; // 默认模型
+    }
+    if (data.stream === undefined) {
+      data.stream = false; // 默认不使用流式返回
+    }
+    if (data.response_format === undefined) {
+      data.response_format = 'url'; // 默认返回图片URL
+    }
+    if (data.size === undefined) {
+      data.size = '2K'; // 默认生成2K图片
+    }
+    if (data.watermark === undefined) {
+      data.watermark = false; // 默认不添加水印
+    }
+    if (data.sequential_image_generation === undefined) {
+      data.sequential_image_generation = 'auto'; // 默认自动处理连续图像生成
+    }
+    if (data.sequential_image_generation === 'auto' && !data.sequential_image_generation_options) {
+      data.sequential_image_generation_options = { max_images: 1 }; // 默认最多生成1张连续图像
+    }
     const res = await fetch(this.apiUrl, {
       method: 'POST',
       headers: {
@@ -27,6 +56,7 @@ export type VolcesImageRequest = {
   sequential_image_generation_options?: {
     max_images?: number;
   };
+  guidance_scale?: number; // 0-10，模型输出结果与prompt的一致程度，即生成图像的自由度；值越大，模型自由度越小，与用户输入的提示词相关性越强
   response_format?: 'url' | 'base64';
   size?: string; // 如 "2K"
   stream?: boolean;
@@ -42,4 +72,39 @@ export type VolcesImageResponse = {
   status: string;
   message?: string;
   [key: string]: any;
-};
\ No newline at end of file
+};
+
+export const size = [
+  {
+    name: '1:1',
+    value: '2048x2048'
+  },
+  {
+    name: '4:3',
+    value: '2304x1728'
+  },
+  {
+    name: '3:4',
+    value: '1728x2304'
+  },
+  {
+    name: '16:9',
+    value: '2560x1440'
+  },
+  {
+    name: '9:16',
+    value: '1440x2560'
+  },
+  {
+    name: '3:2',
+    value: '2496x1664'
+  },
+  {
+    name: '2:3',
+    value: '1664x2496'
+  },
+  {
+    name: '21:9',
+    value: '3024x1296'
+  }
+];