I did a lot of work on I Can Has Cheezburger this weekend, and I now have it more or less usable, although a few UI features are still missing. I rewrote some of my views to take more advantage of Three20, which dramatically improved the performance.
I reduced the memory usage in the LOL Creator (which was always a problem) by not creating a full-sized preview, but only creating the full-sized image when saving or sending. For the preview, I now create the image only large enough to fit in the view (an iPhone camera shot is 1600×1200, although the screen is only 320×240).
Here’s a sample of how it performs on an iPhone 3GS with a WiFi connection.