How to get better quality of addToolButton icon?

Hello together,

I've generated and added my addToolButton icons as described here:

addToolButton - oIcon - Hexadecimal Value

Therefore I'm designing the icon in Photoshop 20 x 20 px, save it as png, render it to hex in Acrobat's console and feed this hex-stream into a variable. The result is a very poor image quality of the icon. Is there a better way to do this? Or have parameters changed and now it's a 256 x 256 px image or Acrobat takes svg or what is it to get a good icon quality?

Thanks,

Tobias