Board Thread:Ask the Staff/@comment-34656790-20180625030606/@comment-5642360-20180701012222

This is one of the main reasons the wiki uses non-rasterized PNG for the character images. It allows you to fill in cells easily. So it's just a matter of filling each cell with the appropriate color.

As for creating the palette, you just need to know colors and whether or not you like how it looks.