I made sure everything is setup the way it should, misc settings adjusted, upload folder rights are set. Image upload works fine tho, it simply doesn't generate thumbnails accordingly.
I'm running WordPress 2.6.1, made sure the GD libs are present and up to date.
Does WP need another tmp folder for thumbnail generation which it can't access maybe? Or any other idea what might prevent WP from generating them?
Help's highly appreciated!