So I have a subclassed UITableViewCell and I have a thumbnail image that is downloaded of the internet from a url (unique to each cell). When each cell comes into view the image is downloaded from the internet, stored in an array for caching, and then displayed. If that cell ever loses visibility and then gets visibility back, it pulls the image from the array instead.
UIImage *myImage = [[UIImage alloc] initWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:thumbnailURL]]];
imageForPosition[cellNumber] = myImage;
self.myCellImageView.image = imageForPosition[cellNumber];
Now this code works fine and the images get downloaded and displayed fine. However, every time a cell first becomes visible, it needs to download the image which makes scrolling appear choppy (not so much on WiFi, but definitely on EDGE).

Does anyone have any suggestions or methods to just display a local "placeholder" image at first and download the image in the background and replace the placeholder when it's ready. In my mind, this would let you see the text in the table as soon as possible and have the thumbnail images load as you need them.