First, open an image - a photo of someone's profile fits best with gold coins - remove any material you don't want and reduce the number of colours by posterizing the image - use Effects:Tonal Control:Posterize
with 8 levels.
Next, create a new gradient from this image
(do a screen dump of this page, open it in Painter, select the gradient and choose Tools:Gradations:Capture Gradation
). Apply this gradient to the image using Tools:Gradations:Express In Image
This is actually the left half (more or less) of the Gold 3 gradient - if you use the whole gradient it doesn't quite work (but try it for yourself and see what you think).
Now we can emboss it by using Effects:Surface Control:Apply Surface Texture
with the following parameters:
Obviously you can do the same with any gradient - try the predefined wood ones. You should be able to create