Students of any age are often able to make use of works created by others under the auspices of fair use. Although fair use is not always an easy concept to fully understand, many student works satisfy some of the more straightforward fair use factors: the purpose of student works is almost always educational, and often also critical or providing commentary. Students are often using published, factual source works. Students are rarely commercial actors.
On the other hand, some student uses are more problematic. Where students are not using a work in order to comment on it, the use may be less likely to be fair (e.g., using a picture just as decoration or to add visual interest, as opposed to including a picture in order to comment on that image.) Also, student uses sometimes borrow large amounts from the heart of creative works, and some student uses substitute for purchases the student (or others) would otherwise have made. These uses also may be less likely to be fair, even when done for an educational purpose.
In-class uses by students (performance or display only, not making or distributing copies) may sometimes be permitted under the Classroom Use Exemption, and film studies students, or students making transformative critical multimedia works may benefit from some of the specific exemptions to the DMCA.