hi,
if you've looked at the archive I would not need to post it, but I found this answer quite usefull here you go:
(hope it helps) cya Rob
I doubt the gd library would be usefull (but check in the doc anyway 😉 ).
If there is no such function available, you can have a look at image magick. This shall let you do what your looking for.
The GD library has "imagecopyresized()"
which is perfect for the job, but it is very basic,
so don't expect DTP quality results. It is enough for most purposes.