Quick Question about Custom Icons

[Vigilante]

So I started making some custom icons (I'm making a few sets), what image size is recommended to work with? It looks like the icons are about/a little under 60x60 pixels, is this correct? Can I make it so the icons are larger than the normal (for a possible 3 per row)? Are they imported as .png files? Thanks.

[csmitty]

i believe they're 59x60 .png. if you have some already on your computer just click them or hold over them and it should tell you.