The Pandigital Photo Viewer application is used to simply display images from the Pandigital digital frames. The software is also capable of transferring images to the device through USB. This is an alternative, because once you connect the device PC, automatically the Mass Transfer mounts a partition in My Computer in order to transfer files.
The Pandigital already has a photo viewer available. It acts as a operating system. You don't need to put another one since it's not possible.