iphone facebook发布流问题

我正在使用iOS facebook DemoApp示例发布到我的个人资料中。它很好用。我的问题是如何在这篇文章中添加图片链接？我使用的代码是：

- (IBAction)publishStream:(id)sender 
{   
    SBJSON *jsonWriter = [[SBJSON new] autorelease];

    NSDictionary* actionLinks = [NSArray arrayWithObjects:[NSDictionary dictionaryWithObjectsAndKeys:
                                                        @"title",@"text",
                                                        @"http://www.link.com/",@"href",
                                                        nil], nil];

    NSString *actionLinksStr = [jsonWriter stringWithObject:actionLinks];
    NSDictionary* attachment = [NSDictionary dictionaryWithObjectsAndKeys:
                                @"This is a name!", @"name",
                                @"This is a caption!", @"caption",
                                @"http://www.link.com/images/log1.png", @"picture",
                                @"This is a long description that goes on an on.", @"description",
                                @"http://www.link.com", @"href",                                
                                nil];

    NSString *attachmentStr = [jsonWriter stringWithObject:attachment];
    NSMutableDictionary* params = [NSMutableDictionary dictionaryWithObjectsAndKeys:
                                   kAppId, @"api_key",
                                   @"Share on Facebook",  @"user_message_prompt",
                                   actionLinksStr, @"action_links",
                                   attachmentStr, @"attachment",
                                   nil];    

    [facebook dialog:@"stream.publish"
            andParams:params
          andDelegate:self];
}

这幅画不会出现。我使用的链接是正确的。该职位获得了成功。我怎样才能让图片链接显示出来

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感谢您的帮助。

Facebook iOS SDK中的示例应用程序有点过时。在回答这个问题时，我详细介绍了发布到用户流的正确方法和相关文档页面