Xcode - UICollectionView ติดปัญหาเวลา Scroll ภาพมันหายไป แก้ยังไงครับ ???

-(UICollectionViewCell *)collectionView:(UICollectionView *)collectionView
                 cellForItemAtIndexPath:(NSIndexPath *)indexPath
{
    
    CustomColumnCell *myCell = [collectionView
                                dequeueReusableCellWithReuseIdentifier:@"myCell"
                                forIndexPath:indexPath];
    
    NSDictionary *tmpDict = [myObject objectAtIndex:indexPath.row];
    
    NSURL *url = [NSURL URLWithString:[tmpDict objectForKey:path]];
    NSData *data = [NSData dataWithContentsOfURL:url];
    UIImage *img = [[UIImage alloc] initWithData:data];
    
    myCell.displayImage.image = img;
    myCell.displayDetail.text= [tmpDict objectForKey:name];

    return myCell;
    
}