Alright, so I pulled a file off of a PS2 game consisting of lots and lots of images. Most of them were uncompressed, but there were some that *were* compressed. I don't know too much about common compression formats among PS2 games, but I do know that LZ/dictionary ones are pretty popular otherwise.

The weird thing is this. Each image has a clear-as-day palette at the start - it lasts 1024 bytes(enough for 256 colors), and then the next four bytes say how big the data for the image is. After that, though, it's garble. Is there anything I can do to identify the compression(if it's known, that is) by just looking at it? I read up on LZ stuff, but I couldn't find any samples of the hex code, so I can't compare anything.

The best way to confirm what compression is uses is to use an emulator with trace functionality and look at what it does to convert the compressed data into the uncompressed output.

I've seen no fewer than three different hand-rolled varieties of LZ used in games (Sylvanian Families 5, Sylvanian Melodies and Mobile Police Patlabor), and all of them used drastically different methods of accomplishing it, so just looking at the data will probably not tell you much.