Use SDWebImage to download an image the display in UITableViewCell with fade in and the image cache build in SDWebImage. https://github.com/rs/SDWebImage

gistfile1.m

#import "UIImageView+WebCache.h"

// load the image in:
// - (void)configureCell:(MyCell*)cell atIndexPath:(NSIndexPath*)indexPath
// or in - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath

NSString *imageURLString = item.imageURL;
if (imageURLString) {
    NSURL *url = [NSURL URLWithString:imageURLString];
    if (url) {
        UIImage *placeholder = [UIImage imageNamed:@"image-shader"];        
        __weak UIImageView *imageView = cell.largeImageView;        

        [cell.largeImageView setImageWithURL:url placeholderImage:placeholder options:SDWebImageRetryFailed 
            progress:nil completed:^(UIImage *image, NSError *error, SDImageCacheType cacheType) {
                if (!error && image) {
                    imageView.image = image;
                    if (cacheType != SDImageCacheTypeMemory) { // fade in only on first download
                        imageView.alpha = 0.0;
                        [UIView animateWithDuration:0.30 animations:^{
                            imageView.alpha = 1.0;
                        }];
                    }
                    else {
                        imageView.alpha = 1.0;
                    }
                }
            }];        
    }
}