在UITableView图像上滚动非常慢

Question

非常慢地滚动UITableView张图片。请帮助我。 没有找到合适的解决方案 我的代码：

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *const ImageCellId = @"ImageCell";

    EXImageCell *cell = [tableView dequeueReusableCellWithIdentifier:ImageCellId];
    RSSItem *item = [_data objectAtIndex:indexPath.row];
    cell.cellTextLabel.text = item.title;
    cell.cellTimeTextLabel.text = [NSDateFormatter localizedStringFromDate:item.pubDate dateStyle:NSDateFormatterMediumStyle timeStyle:NSDateFormatterShortStyle];
    cell.cellAuthor.text = [NSString stringWithFormat:@"Author: %@", item.author];

    NSURL *tutorialsUrl = item.link;
    NSData *tutorialsHtmlData = [NSData dataWithContentsOfURL:tutorialsUrl];
    TFHpple *tutorialsParser = [TFHpple hppleWithHTMLData:tutorialsHtmlData];
    NSString *tutorialsXpathQueryString = @"//div[@class='photo']/img";
    NSArray *tutorialsNodes = [tutorialsParser searchWithXPathQuery:tutorialsXpathQueryString];
    //NSMutableArray *newTutorials = [[NSMutableArray alloc] initWithCapacity:0];
    for (TFHppleElement *element in tutorialsNodes) {
        tutorial = [[Tutorial alloc] init];
        //[newTutorials addObject:tutorial];
        //tutorial.title = [[element firstChild] content];
        tutorial.url = [element objectForKey:@"src"];
    }
    NSData *data = [NSData dataWithContentsOfURL : [NSURL URLWithString:tutorial.url]];
    UIImage *imageMain = [UIImage imageWithData:data];
    [cell.cellImageView setImage:imageMain];

    return cell;
}

PS：dispatch_async试图使用，但无济于事