Does the electronic jpg format of photographic works need to be changed to print?

It depends on the requirements of the film festival.

If you need to print, one is to look at the highest pixel of the printer, the other is to have photo printing paper, and the third is to look at the printer's requirements for photo format. You can usually print JPG. Because, the resolution of general color printing is far lower than the pixels of photos. So if it's a photographic work, it's better to send it to the studio for printing.