Cannot set thumbnail image for UIWebView

I want to set thumbnail image in the uiwebview frame on my view. However when I use the following code, there is no image displayed, although the image value is NOT NULL. Can someone help and and let me knwo where am I going wrong?

Please note that in the code, the VideoView class is derived from UIWebView and works just like it.

        video = [[VideoView alloc] 
                              initWithStringAsURL:@"http://www.youtube.com/watch?v=T6X3j7zxUHA" 
                              frame:CGRectMake(11, 7, 298, 311)];

    [self addSubview:video];

    UIGraphicsBeginImageContext(video.bounds.size); 
    [video.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *resultImageView = UIGraphicsGetImageFromCurrentImageContext();

    thumbnailButton = [UIButton buttonWithType:UIButtonTypeCustom];
    [thumbnailButton setFrame:CGRectMake(0,0, 298, 311)];
    [thumbnailButton setImage:resultImageView forState:UIControlStateNormal];
    [video addSubview:thumbnailButton];
     UIGraphicsEndImageContext();

Solution

I would not recommend using a UIWebView to just get a thumbnail of a YouTube video, but here is some code that I use to embed youtube videos in my app.

static NSString* EmbedHTML = "<html>\
<head>\
<meta name=\"viewport\" content=\"initial-scale=1.0, user-scalable=no, width=%0.0f\"/>\
</head>\
<iframe width=\"%0.0f\" height=\"%0.0f\" src=\"%@\" frameborder=\"0\" allowfullscreen>   </iframe></html>";

Use that to embed the video and change your youtube URL from http://www.youtube.com/watch?v=T6X3j7zxUHA to http://www.youtube.com/embed/T6X3j7zxUHA.

Another way to get this that would not require the webview, would be to just build the thumbnail by hand. (example below)

  ///////////////////////////////////////////////////////////////////////////////////////////////////
-(NSString*)youtubeThumb:(NSString*)url
{
    NSRange end = [url rangeOfString:@"?"];
    if(end.location != NSNotFound)
    {
        NSRange start = [url rangeOfString:@"/" options:NSBackwardsSearch range:NSMakeRange(0, end.location)];
        if(start.location != NSNotFound)
        {
            NSString* video_id = [url substringWithRange:NSMakeRange(start.location+1, (end.location-1)-start.location)];
            return [NSString stringWithFormat:@"http://i.ytimg.com/vi/%@/2.jpg",video_id];
        }
    }
    return nil;
}

Now you have the image thumbnail URL, just fetch it (via a simple GET request).