If the size of the compressed file is significant, is a JPEG the best option every time? I'm thinking of transmaps for eyelashes -- how many colours do they use? I'm thinking they're greyscales, so they don't need 24-bit colour. One transmap I've been working on is plain black and white, and I saved it as a 2-colour PNG file. Which works fine in Poser 5. The other advantage over a JPEG for that file is that I don't get those blurred edges. But am I just saving disk space (or download time)? Or does it make rendering a bit less memory-hungry?