It depends on if the formatting took place before or after the photos were added. It also may be the photos are in one partition and the formatted drive may have been another partition so you would be ok in this scenario. You can only try it. If you can navigate to the drive & folder the photos are supposed to be in you may be able to recover them. Even if the folder is gone there is a slim, and very slim, chance you may still be able to recover them with an undelete tool. This will only work if there has not been a lot of drive read/writes that may have used the addressing space the photos were stored in.