Each pose will have a .png file with the same name. OPen the .png file in a program such as Paintshop Pro or the like and edit away. As long as you save it with the same name as your pose you will be fine. The dimensions of these .png files are 91 x 91 pixels. If you encouter any problems try repeating this but do not alter the very first pixel (Top left corner). Have fun. Hope to see these mat files when you're done.