This is not an obvious hint: have you ever thought about the photos you need to shoot during the making of the film?
I know, somebody may think of extracting frames from the film and go away with it – but this is the wrong choice. The best thing you can do is to hire a professional photographer to shoot live on set, even for just a couple of hours.
When your short film photos will be published on festival catalogues, they will represent your work. Therefore, they need to be beautiful and professional.
Remember to add the “photographer” voice in your budget list!