Exactly what you want to do is not clear to me.
Trying to 'fake' the missing bits of photo is, while possible, a very
time consuming choice.
I think you would be better off making it seem like the missing bits
are intentional, as in this example:
I made this by:
1. rotate appropriately.
2. apply 'value propagate', propagating opacity to the left and right
only, repeatedly until no transparent pixels are left.
3. remove the streak that appears near the top of his head by a bit of painting.
is another idea, made simply by a bit of strategic painting. It
emphasizes the focus on the book.
Gimp-user mailing list