I cannot seem to find any information about this question. Is it appropriate to include photos of characters in a biographical screenplay?
The two screenwriting books I've read warn that professional reviewers with a stack of scripts "to finish by Monday" start by tossing out the ones that don't conform to established conventions. These scripts tend to be written by inexperienced writers and have a lower likelihood of becoming successful films. Including photographs seems unconventional. If your screenplay makes it into production, you can supply the photographs to the researchers assigned to the project. If you're writing for a more personal audience, then including the pictures seems like a good idea.
Have to agree with rolfedh. As a professional reader I always get uneasy when I receive an "unconventional" script. The main reason for this is that it suggests that the writer couldn't find a way to express what they mean in the script itself, and had to somehow bolster their work with additional material that will never make it to the screen. If your photo's are actually going to appear, and showing the stills contributes to the story then great. If not, or if they are meant to improve the script as a document, then don't. Additional advice available at www.shorescripts.com. Best wishes with the writing.