Are those blank discs compatible to be used for pictures too?
Usually when you copy photos (or any types of data) to discs your CD or DVD burner will have stage to finalise your discs which is usually towards the end of copying process. It usually does automatically towards the end of copying process so that the photos can be played back on standard dvd players (whether the one on your computer or standard alone dvd players).
Like Ethel said, to play back photos, region free has nothing to do with it.