微信分享

// 微信，缩略图的尺寸为300*300
- (IBAction)wx:(id)sender {
    WXMediaMessage *message = [WXMediaMessage message];
    [message setThumbImage:[self scaleFromImage:shareImage toSize:CGSizeMake(300, 300)]];
    
    WXImageObject *ext = [WXImageObject object];
    ext.imageData = UIImagePNGRepresentation(shareImage);
    message.mediaObject = ext;

    SendMessageToWXReq *req = [[SendMessageToWXReq alloc] init];
    req.bText = NO;
    req.message = message;
    req.scene = WXSceneSession;
    [WXApi sendReq:req];
}

微信iOS SDK文档 1.4.2