We want to make sure the
original is of a similar color to our new frame, because some pixels around
the edges will inevitably show through, so I did an overlay of the yellowish-brown
color that is in the new frame
Now copy and pase your new
frame on top, and use the "distort function.
Basicly, "distort" gives
you little handles on the corners of the selection. Just move them to line
it up with the front of the old painting.
(I use Fractal Design Painter
5 for my paint program, but most other programs have the same functions,
although they might be under different names.)