Hi Cornel, yes like Burr writes above the icons for Max's CustomUI mod are embedded in the .js files that you copied into the startup folder.

There is some description on how to edit those to load a PNG image file here:
http://moi3d.com/forum/index.php?webtag=MOI&msg=9138.12

- Michael

Thanks guys,
I had no idea those were in base64.
I'm good from here.