docs: tranlation for image-picker, ref #329

components/image-picker/index.en-US.md

@@ -4,7 +4,7 @@ type: Data Entry
 title: ImagePicker
 ---
 
-注意：只是图片选择器，一般用于上传图片前的文件选择操作，但不包括图片上传的功能
+Note: Just for selecting picture. Generally `ImagePicker` is used to select picture before uploading, but without the feature of uploading.
 
 
 ## API
@@ -13,10 +13,10 @@ Support WEB, React-Native.
 
 Properties | Descrition | Type | Default
 -----------|------------|------|--------
-| files    | 图片文件数组,元素为对象,包含属性 url（必选, 可能还有id, orientation, 以及业务需要的其它属性     | Array  | []  |
-| onChange    | files 值发生变化触发的回调函数, operationType 操作类型有添加，移除，如果是移除操作，则第三个参数代表的是移除图片的索引  | (files: Object, operationType: string, index: number): void |   |
-| onImageClick(`web only`)    | 点击图片触发的回调  | (index: number, files: Object): void |   |
-| onAddImageClick(`web only`) | 自定义选择图片的方法  | (): void |   |
-| selectable(`web only`) | 是否显示添加按钮  | boolean |  true |
+| files    | Picture files array which includes `url`(required) in each object | Array  | []  |
+| onChange    |   Callback is called when the value of `files` is changed. The `operationType` is one of `add` or `remove`(the third argument is the removed index).| (files: Object, operationType: string, index: number): void |   |
+| onImageClick(`web only`)    | Callback is called when the user clicks the selected picture | (index: number, files: Object): void |   |
+| onAddImageClick(`web only`) | Callback is called when the selector button is clicked   | (): void |   |
+| selectable(`web only`) | whether to show selector button  | boolean |  true |
 
-> 注: RN 版本回传 assets-library (性能考虑)，需要使用 native 模块进行上传，可参考 https://github.com/facebook/react-native/issues/201
+> Note: Only return assets-library type for RN, if you want to upload files, see https://github.com/facebook/react-native/issues/201