C#.... I'm pretty sure I came across one created by the creator of NSE that was public. Make sure you give credit if you find it. The images follow the LZ77 compression algorithm, which isn't too hard. It does take a bit of trial and error to code though. Took me a few days to finally get it even with actually asking a lot of people for help. I can't really remember how to decompress and re-compress unfortunately, otherwise I would tell you how to.
Anyways, I haven't seen you for a while, how you been?