Color in existing .jpg or .png

[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.