Understanding true color data

Retro Graphics toolkit stores true color data in addition to the converted tiles. This makes it easier to change the palette. Simply re-dither. Also note that alpha data is also stored. Transparent data will be dithered and assigned color 0.

The advantage of preserving this data is traditionally when you wanted to make a change to the palette you would have to redraw all graphics or go through a (less but still very laborious) process of manually loading the image in an image editor and applying the new palette for all images. Retro Graphics Toolkit automates this process.