Using copyrighted images in school projects without permission can constitute copyright infringement, but there are exceptions under the fair use doctrine. Fair use allows limited use of copyrighted material for purposes such as criticism, commentary, news reporting, teaching, or research.
When determining if the use of a copyrighted image falls under fair use, factors to consider include the purpose and character of the use (e.g., is it for non-profit, educational purposes), the nature of the copyrighted work, the amount and substantiality of the portion used, and the effect of the use on the potential market for or value of the copyrighted work. As a general guideline, using small portions of an image for educational, non-commercial purposes is more likely to be considered fair use than using a large portion or the entire image. It's important to keep in mind that fair use is determined on a case-by-case basis and can be complex, so when in doubt, it's best to seek permission from the copyright holder or use images that are licensed for free or open use.