Here are some different coloured versions of the skill panel buttons, plus 'blank' versions of the buttons which have icons (paws, restart, nuke, etc) so that you can make your own custom skill panel!
I recommend using
paint.net for graphics editing, it's a free but powerful app that's regularly updated and is very easy to use. Make sure to keep the images in
.png format.
Place your customised panel graphics into
SuperLemmix/gfx/panel for low-res, and
SuperLemmix/gfx/panel-hr for hi-res, to install them. Post a reply here if you have any questions/issues.
Enjoy!