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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).