I have only quickly skimmed through GIL docs, so I don't know if GIL provides *processing* algorithms. It would be nice to have that. But maybe due to the fact the the number of such *processing* methods is almost infinite (just look at how many plugins GIMP has) I rather expect this library to provide an easy interface to implement any (and all) of those that you mentioned above.
I agree. I didn't mean to suggest that all the above should be added to GIL itself. Rather, my point was that there are many situations where images are dealt with in a non-interactive (and, in particular, non-GUI) way.
Stefan and Janek: As you pointed out, there are infinitely many algorithms that can work with images. All we can do in GIL core is to provide the framework that you can use to write your algorithms. We are hoping other developers can join us and contribute algorithms. One possibility is that we have an "algorithm" extension to GIL possibly as a follow-up submission. Lubomir