自定义网络请求图片的大小

NSURL *url = [NSURL URLWithString:[[self.imageSource objectAtIndex:indexPath.section] objectAtIndex:indexPath.row]];

UIImage *icon = [UIImage imageWithData:[NSData dataWithContentsOfURL:url]];CGSize itemSize = CGSizeMake(30, 30); UIGraphicsBeginImageContextWithOptions(itemSize,NO,0.0); 

CGRect imageRect =CGRectMake(0.0,0.0, itemSize.width, itemSize.height); 

 [icon drawInRect:imageRect];

 cell.imageView.image =UIGraphicsGetImageFromCurrentImageContext(); UIGraphicsEndImageContext();