PNG Floyd saves a super hi-res screenshot¡Kas a PNG graphic. Although the PNG file format is well documented and standardized, the compression (deflate) is not nearly as nice ¡X the RFC suggests looking at the source code for zlib, which is an amazing mess. I spent a fair amount of time looking at file dumps of small png graphics to get a handle on how the compression was working, and then used a perl script to verify my compression output could be uncompressed. For compression, I only did a 1-byte run length encoding, and I only compress one line of the image at a time, so recompressing would be a good idea. Supporting multi-byte RLE could help the compression, as would using 4-bit graphics (if 16 colors or less).