08-27-2019, 06:37 AM (This post was last modified: 08-27-2019, 06:48 AM by Ofnuts.)
See the "attachments" link at the top for instructions.
You can paint over the lines (and the black dots in the stone) by either:
adding a layer, setting it to Multiply mode and painting on it with a tool in Normal mode. You can have a single layer but it could be more convenient in the end to have one per color (so that you can easily change that color later)
painting directly on the layer with a tool in Multiply mode.
08-27-2019, 01:01 PM (This post was last modified: 08-27-2019, 01:02 PM by rich2005.)
This is one case where small is not a great advantage. As downloaded, only 316x247 pix. I would not even think about bucket fill. Make plenty layers and paint under the original.
First of all give the original transparency. Layer -> Transparency -> Add Alpha Channel Then remove the white, leaving the outline. Colors -> Color to Alpha (white is the default)
Then plenty of layers, one for each colour / area and paint in. The order of the layers does matter, a higher layer masks a lower layer, so think about it.
The only snag is a white? stone, I had to make this on its own from the original, erase and adjust before adding right at the top of the stack. I think a bit of texture is best - up to you.
All-in-all not as straight forward as you might expect.
With the .xcf file provided by Rich2005 you can change the colors to your liking and get the tone you prefer.
I tried with a magnification using inkscape, but the texture got lost in that way, still an option.