The referenced pictures are not stored in FileMaker. They are stored on your local hard drive. The other users on the network don't have access to your local hard drive (and even if they do the path to them looks different than what FileMaker has stored as the path).
This is only going to work if you store the images on a shared network drive. and there is still going to be complications in making sure that drive "looks" the same to everyone so that FMP will see the images.
thanks for your help!