Is it illegal for schools to use students' works without authorization?

You are a photographer in school. If you learned your photography skills in a school training class and your work is still a training exercise, then the work belongs to a "job work", and its copyright belongs to the school, which has the right to use it.

If your technology has nothing to do with the school and you use your own photographic equipment to complete the work, then the copyright belongs to you completely. It is an infringement of your rights for the school to publish your works without the permission of the copyright owner. You can ask the school to compensate and restore your right of authorship according to the provisions of the copyright law (confirm that you are the author through a "correction statement" in the publicity publications on or off campus where the work was originally published).