依次点击链接请查看以下步骤

选择图片：

https://mp.weixin.qq.com/debug/wxadoc/dev/api/media-picture.html#wxchooseimageobject

查看图片信息：

https://mp.weixin.qq.com/debug/wxadoc/dev/api/media-picture.html#wxgetimageinfoobject

浏览图片:

https://mp.weixin.qq.com/debug/wxadoc/dev/api/media-picture.html#wxpreviewimageobject

图片上传:(需要后台接口把选取的图片路径转换成后台存储图片的路径)

https://mp.weixin.qq.com/debug/wxadoc/dev/api/network-file.html#wxuploadfileobject