I have a table view that's scrolling slowly. Does anyone know why that might be?

There is an image for each row, but even after the images are loaded it still stutters and scrolls slowly.

thanks for any help

here's my code:

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *simpleTableIdentifier = @"SimpleTableCell";

    SimpleTableCell *cell = (SimpleTableCell *)[tableView dequeueReusableCellWithIdentifier:simpleTableIdentifier];
    if (cell == nil)
    {
        NSArray *nib = [[NSBundle mainBundle] loadNibNamed:@"SimpleTableCell" owner:self options:nil];
        cell = [nib objectAtIndex:0];
    }
    // Get item from tableData
    NSDictionary *item = (NSDictionary *)[displayItems objectAtIndex:indexPath.row];

    // display the youdeal deal image
    photoString = [item objectForKey:@"image"];
    UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:photoString]]];

    cell.titleLabel.text = [item objectForKey:@"supercat"];
    cell.descriptionLabel.text = [item objectForKey:@"title"];

    NSString *convertedLeftCount = [NSString stringWithFormat:@"%@",[item objectForKey:@"left_count"]];

    cell.amountLabel.text = convertedLeftCount;

    cell.thumbnailImageView.image = image;
    cell.priceLabel.text = [item objectForKey:@"cat"];

    return cell;
}