JC, The converter doesn't handle compressed files so in photoshop, make sure you save your tiff as uncompressed. As for whether the converter handles pgms better than PSP I couldn't say - I decided not to handle PSP for the reasons that I don't have PSP so I couldn't test it out, I don't know how versitile PSPs conversion process is and a another reason that I won't mention here which nonetheless should become obvious as you read over the associated threads. Max, Right now I'm not even thinking of releasing my source code but the tiff specification should be available from Adobe and the PGM format is really simple. If you do a google search for PGM, you should find access to the spec such as it is there really isn't all that much to it. The Tiff format on the other hand, takes a little time to figure out, and it's relatively complicated compared to the BMP or TGA formats but is really versitile. It all boils down to binary to text conversion and to some degree pixel(data) manipulation. If you need a hand getting started in developing it for MAC after looking at the tiff spec, contact me by IM. - TJ