Little Dragon sez: "JPEG supports 8-bit grayscale. Works fine with Poser, too. " It depends on the software used to save the image A lot of the "grayscale" JPEGs that I've seen used for transparencies are basically desaturated RGB images which, while they work in Poser, they still require a lot more memory than an image set at the proper bit depth. Some apps, like Photoshop save JPEGs in true 8-bit grayscale, other apps save grayscale JPEGs as 24-bit color image files. The best route would be to resave the transmap as a true 8-bit image. If you open a transparency file, and the image shows a grayscale image containing three identical RGB channels instead of a single "Black" (or "Gray") channel, then it has NOT been saved as a true grayscale. RGB channels for transmaps are a waste of memory that is better used loading other models, textures and transmaps into your scene. The Poser manuals (since P1) all suggest that reducing the bit depth (where applicable) will actually improve performance.