Have you verified through SSH that it works? I beleive Luciano pointed out the imagemagick that your host installed did not work earlier in this thread. Just because your says its installed does not mean its functional.
Here is an example if your image processor is set to imagemagick this is what happens dscn0516 - البوم صور منتدى مسافرون
The image is suppose to be resized down to 1500 pixels and then a thumbnail gets created from what I see. On your server no images are being created so no images get done not much thumb. The only thing happening is an image is upload. No image processor is functional on your server.