Copyright holders hold rights to all aspect of the film: story, images, and music.

Legally, film stills are protected by copyright.

There are two legal ways to use copyright materials:

1. Fair Use = use of copyrighted material for a limited and “transformative” purpose, such as to comment upon, criticize, or parody the work
2. Newsworthy = use of copyrighted material for appropriate, timely, and "newsworthy" material

"Transformative" and "newsworthy" can be subjective so it depends on how strong your case will be.

If your project falls under fair use or high newsworthiness, you may have a strong case to use the copyrighted material. Otherwise, the copyright holder may go after you.

In practicality, it also depends on whether or not the copyright holders will choose to enforce it. If it's intended for personal, non-commercial use, then it might not be worth their time and public image to pursue it.