关于AFNetworking上传图片问题

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];

[manager POST:@"XXXX"  parameters:nil constructingBodyWithBlock:^(id<AFMultipartFormData> formData) {
NSData *imageData = UIImageJPEGRepresentation(_userImg, 1);
 
// 上传图片，以文件流的格式 name 对应网站上[upload.php中]处理文件的[字段"file"] fileName 不能为空且必须带后缀，如：test.jpg
[formData appendPartWithFileData:imageData name:@"photo" fileName:@"XXXX.jpg" mimeType:@"image/jpeg"];

 } success:^(AFHTTPRequestOperation *operation, id responseObject) {
[_activityView stopAnimating];
if ([[responseObject objectForKey:@"success"] intValue] == YES) {
[self makeToast:@"头像修改成功！" duration:2.0 position:@"bottom"];
[self saveUserInfo:[responseObject objectForKey:@"data"] key:@"avatar"];
}else{
id data = [responseObject objectForKey:@"data"];
[self makeToast:[data objectForKey:@"message"] duration:2.0 position:@"bottom"];
}
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
[_activityView stopAnimating];
[self makeToast:@"网络不给力!" duration:2.0 position:@"bottom"];
}];