Colors

There are 24 colors in the game, all with different affects on the stats of a frog.

Imitating how the game does it
The way I've found how to imitate the game's rendering is to use paint.net, and its recolor tool, with recoloring pure white to the color.

An example and template paint.net project can be found here. The textures of all the frog patterns can be found here.