You could use this too and it is free
http://www.virtualdub.org/blog/pivot/entry.php?id=79Yes it is for video but you could use it anyway.
Simius i think you know how to do these things!
The technique Virtualdub uses looked very (even too much) similar as the old "Genuine fractals"
(it seems they used the same method only labeled as fractal resizing. Only guessing of course! )
and i think maybe the new one "One on one" is the same probably.
There was one script-plugin for Gimp that uses the same method. Free . You have to search.
It could work but i would test it before .
Nothing is good as in native resolution for me , so you have to see if you like it or not.
Found my own post:
http://www.planetside.co.uk/forums/index.php?topic=12849.msg127776#msg127776There are the Gimp links too.
The thread in general is about resizing. Take a look if you will.