[Gimp-user] Reduce the number of colors on a selection

[Chris Mohler]

Maybe this:

1. Copy your selection
2. Edit->Paste as New
3. Image->Mode->Indexed
4. Image->Mode-RGB
5. Select All
6. Copy
7. Paste back into original image

I used to do something similar in Photoshop when I wanted to bitmap
just a portion of an image.

HTH,
Chris