@onnetz: You know, perhaps I'm seeing what I want to see. Especially in relation to UV mapping, several people suggest to use powers of two, though I grant you that textures CAN be rectangular - and are made more efficient by being powers of two because they are faster to access. I'm not sure if you're playing devil's advocate or if you seriously believe that a 537*723 is more or less memory drain than a 512^2 texture. I hope the former is true. For mental ray AND Renderman which both efficiently cache textures, you would convert your textures to mip-maps (the application specific names are different). The documentation for both of these production quality render engines RECOMMEND that you output should be power of two; the resulting mip-map WILL be square. Since Firefly is Renderman-compliant, then it stands to reason that Poser could benefit from the same texture treatment. I say this with the greatest respect and humility, but I'll rescind everything I've said if you can produce a compelling argument that would dissuade me from the advice of software engineers and programmers. I would be happy to provide you with ISBN numbers to support my view.