The files to tweak are stored in heads/xcf and should be tweaked only there. Please leave the original image in a layer; if you want to weak it directly instead of creating an overlay, duplicate it into another layer and just hide the original one. Also, please strike through the heads you have tweaked in the overview in http://titanpad.com/tOLXLvwzpo so that the titanpad can be used for tracking purposes. You might want to add a "working on" mark after images, if you want to avoid duplications, but please don't block them for too long. NOTE: As the XCF to PNG final conversion was made, any new alterations of the heads will need to be saved both as XCF and PNG format. Please use the designated heads/joke-{png,xcf} directories to save them. Have fun hacking gotchis!