If it is indexed the you can edit the color map directly for any color that is included in the map. However, there is no noticeable anti-aliasing there, so check the color mode of the original image (or is the one you posted the original?) Look at the top of the Gimp window, does it say RGB or Indexed?
After cut, increase the selection by a pixel to give a clean edge & fill on a layer underneath. Often you need to cut then fill underneath to eliminate a remaining border of semi-transparent pixels - anti-aliasing used to smooth lines. There is at least one filter for replacing colors in the gmic plugin, That one might not work so well with that image.Īs dinasset described, color select, and fill works with the screenshot you posted. The stock gimp tools are in Color -> Map menu You might find something there.
