update doc

doc/SHARE.md

-### Summary
+## Summary
+
 `Fluwx` doesn't support all kind of sharing.Only text, image, web page,
 music, video and mini program are supported.We'll consider the more.
 More support will be considered in the future.
 .
 
+> NOTE：Images or thumbnails used for sharing only support `png`and`jpg`
+
+### What kind of images are supported
+
+- Network images
+  
+- Assets Images
+
+- Local Images
+  
+However, developers must care about the following points:
 
- >  NOTE：Images or thumbnails used for sharing only support `png`and`jpg`.Network or assets images are OK.<br>
- >  However,using images from `assets`,you have to add a schema `assets://`。<br>
+- Provide  schema `assets://` when using assets images.Query `?package=package_name` is neccessary when load images from particular package. Here's a full exmaple:`assets://path/to/your/image.png?package=fromPackage`
+- Provide  schema `file://` or `content://` when using local images, but `content://` only works on Android due to `FileProvider`.For example, `content://media/external/file`
+- Otherwise, network images by default.
+- `Fluwx` will create thumbnail from main image if no thumbnail is provided. 
+- Due to the limits of WeChat，the thumbnail must be smaller than 32k(mini-program's is 120k),  `Fluwx` will compress images before sharing if thumbnail is larger than that. But the result of compression is unpredictable.
+    
+ .Network or assets images are OK.<br>
+ >  However,using images from `assets`,you have to add a schema `assets://path/to/your/image.png?package=fromPackage`。<br>
  >  For assets image from  a particular package,you have to add a query param:`?package=package_name`<br>
  >  If you want to use local image,`file://` must be provided.For example, a local image path should be "file://path/to/your/image.jpg". <br>
  >  If no schema or wrong schema provided,`Fluwx` will load it as network image.Be careful<br>
@@ -14,7 +32,8 @@ More support will be considered in the future.
  >  a qualified thumbnail.Otherwise, `Fluwx` will compress it for you. The result of compression is unpredictable.<br>
  >  Considering that we may obtain a path such as *content://media/external/file* on Android, `fluwx` also support reading image or thumbnail from `content://`.<br>
  >  `content://` only works on Android.
-### The Destination
+
+## The Destination
     The destination of sharing can be SESSION(default),TIMELINE or FAVORITE.However,mini-program only support SESSION.
 ```dart
     ///[WeChatScene.SESSION]会话
@@ -26,17 +45,10 @@ More support will be considered in the future.
       FAVORITE
       }
 ```
-### Return
- the return value of `fluwx.share(model)` is `Map`：
-```dart
-    {
-       "platform":"Android",//or iOS
-       result:true //or false，depends on WXApi.sendRequest()
-     }
-```
 
 
-### Share Text
+
+## Share Text
 ```dart
   fluwx.share(WeChatShareTextModel(
       text: "text from fluwx",
@@ -44,7 +56,7 @@ More support will be considered in the future.
       scene: scene
     ));
 ```
-### Share Image
+## Share Image
 ```dart
  fluwx.share(WeChatShareImageModel(
         image: _imagePath,
@@ -55,7 +67,7 @@ More support will be considered in the future.
 ```
 >  NOTE：`Fluwx` will create thumbnail from `image` if thumbnail isn't provided.
 
-### Share Music
+## Share Music
 ```dart
   var model = WeChatShareMusicModel(
       title: _title,
@@ -69,7 +81,7 @@ More support will be considered in the future.
 ```
 Two kind of music：`musicUrl`和`musicLowBandUrl`.They are not coexisting，if both are assigned, only`musicUrl` will be used.
 
-### Share Video
+## Share Video
 ```dart
    var model = new WeChatShareVideoModel(
      videoUrl: _videoUrl,
@@ -83,7 +95,7 @@ Two kind of music：`musicUrl`和`musicLowBandUrl`.They are not coexisting，if
 ```
 Two kind of video:`videoUrl`和`videoLowBandUrl`.They are not coexisting，if both are assigned, only `videoUrl` will be used.
 
-### Share Mini Program
+## Share Mini Program
 ```dart
  var model =new WeChatShareMiniProgramModel(
       webPageUrl: _webPageUrl,

doc/SHARE_CN.md

-### 简述
+## 简述
+
 目前`Fluwx`并不是支持所有的分享类型，目前仅支持文本分享、图片分享、网址分享
     音乐、视频以及小程序的分享。未来会考虑增加更多支持。
 
+### 都支持什么图片
+
+- 网络图片
+  
+- Assets图片
+
+- 本地图片
+  
+但是, 需要注意以下几点:
 
- >  注意：目前分享中涉及到图片的地方仅支持`png`和`jpg`，支持网络图片及`assets`图片。<br>
- >  使用`assets`图片需要添加`assets://`。<br>
- >  也可以在`assets`图片添加`?package=package_name`以读取指定包的图片。<br>
- >  如果你想使用本地图片请勿必提供`file://`，比如`file://path/to/your/image.jpg`。<br>
- >  如果不指定schema或者schema错误,将会被处理为网络图片，请谨慎。<br>
- >  由于微信的限制，一般的缩略图要小于32k(小程序的缩略图要小于120k)，所以在使用缩略的时候<br>
- >  很有必要使用一张合格的缩略图，否则`Fluwx`进行压缩，其结果可能并不是你所预期的。
- >  考虑到在`Android`上，我们可能得到像*content://media/external/file*这样的路径, `fluwx` 也支持从`content://`中读取图片或者缩略图.<br>
- >  `content://` 只在Android上有效。
+- 如果使用Assets图片，请务必提供前缀 `assets://` .如果想加载指定包的图片请加上查询参数 `?package=package_name` 。 例子：`assets://path/to/your/image.png?package=fromPackage`。
+- 如果使用本地图片，请务必提供前缀`file://` 或者 `content://`，但 `content://` 只在Android上有效，因为有的图片可能是从`FileProvider`得到的，例如, `content://media/external/file`
+- 默认当作网络图片处理。
+- 如果不提供缩略图，`Fluwx`将会尝试从主图片中创建缩略图。 
+- 由于微信的限制，一般的缩略图要小于32k(小程序的缩略图要小于120k)，所以如果缩略图不符合规格，`Fluwx`将执行压缩。 其结果可能并不是你所预期的。
+
+## 分享去处
 
-### 分享去处
     绝大部分分享可以分享到会话，朋友圈，收藏（小程序目前只能分享到会话）。默认分享到会话。
 
 ```dart
@@ -26,16 +33,9 @@
       FAVORITE
       }
 ```
-### 返回值处理
- `fluwx.share(model)`返回的是一个`Map`：
-```dart
-    {
-       "platform":"Android",//或者iOS
-       result:true //或者false，取决于WXApi.sendRequest()的结果
-     }
-```
 
-### 分享文本
+## 分享文本
+
 ```dart
   fluwx.share(WeChatShareTextModel(
       text: "text from fluwx",
@@ -43,7 +43,9 @@
       scene: scene
     ));
 ```
-### 分享图片
+
+## 分享图片
+
 ```dart
  fluwx.share(WeChatShareImageModel(
         image: _imagePath,
@@ -52,9 +54,11 @@
         scene: scene,
         description: "image"));
 ```
->  注意：如果不指定 `thumbnail`，那么`Fluwx`将尝试从`image`中获取缩略图。
 
-### 分享音乐
+> 注意：如果不指定 `thumbnail`，那么`Fluwx`将尝试从`image`中获取缩略图。
+
+## 分享音乐
+
 ```dart
   var model = WeChatShareMusicModel(
       title: _title,
@@ -66,9 +70,12 @@
 
     fluwx.share(model);
 ```
+
 音乐的分享有两种：`musicUrl`和`musicLowBandUrl`。这两种形式是不共存的，如果
 都二者都进行了赋值，那么只会读取`musicUrl`。
-### 分享视频
+
+## 分享视频
+
 ```dart
    var model = new WeChatShareVideoModel(
      videoUrl: _videoUrl,
@@ -80,9 +87,12 @@
    );
    fluwx.share(model);
 ```
+
 视频的分享有两种：`videoUrl`和`videoLowBandUrl`。这两种形式是不共存的，如果
 都二者都进行了赋值，那么只会读取`videoUrl`。
+
 ### 分享小程序
+
 ```dart
  var model =new WeChatShareMiniProgramModel(
       webPageUrl: _webPageUrl,