>Michel, basically this is a school and they use these tools for their students in art, computer-tech, etc. The school licensing fees are very high. But these are not professional users and I wonder whether free tools would suffice just as well ?

PhotoShop and Illustrator are highly professional. What you have in there would not be available as is for free. If it would have been just for converting image type to something else, resizing, redimensioning, crop and so on, I would have suggested something like LViewPro for example. But, when comes time to change the artwork in an image, I use PhotoShop.