应用程序崩溃在iPhone中

Question

在UITableView中实现pull to refresh之后，我尝试了4到5次我的应用程序崩溃......

setImage上的EXC_BAD_ACCESS。

cell.thumbnail.image = [UIImage imageNamed:@"noimage.png"];

dispatch_async(concurrentQueue, ^{

    NSString *imageURL = [currentArticle objectForKey:@"Image"];
    NSData *imageData = [[NSData alloc] initWithContentsOfURL:[NSURL URLWithString:imageURL]];
    UIImage *image = [[UIImage alloc] initWithData:imageData];


    dispatch_async(dispatch_get_main_queue(), ^{

    [cell.thumbnail setImage:image];

    });
});