If you have time to kill & like to fiddle with textures for 3D or 2D for image editors this blast from the past is pretty cool... Has a 3D preview window as well-
https://web.archive.org/web/20070209125659/http://www.stud.tu-ilmenau.de/~aiin-in/texture_editor.zip
https://web.archive.org/web/20070209125659/http://www.stud.tu-ilmenau.de/~aiin-in/texture_editor.zip
