If the photos are simply on the disk as data, then there should be no problem playing them in any computer. Any half way competent picture viewer can do this, including the ones built into MS Windows, Linux or Mac OS. The individual may have included captions in German, but you should still be able to see the pictures.
In other words, there is no special format for Germany that cannot work in American computers to view data on a cd. If you want to make a copy, that process is no different than copying any data disk. Either drag and drop the contents, or make an ISO using ImgBurn and then burn the resulting ISO to a blank disk.
If the pictures have been made into a dvd slideshow, then you might run into problems with PAL vs NTSC when playing on a stand alone player. On a computer it would play with no problems using any media player with dvd support...like VLC media player. www.videolan.org
A video cd slideshow should be playable on any computer also. If the pictures have been made into a slideshow, use ImgBurn to make an ISO and burn it that way when you copy the disk. www.imgburn.com
On the off chance that what you are asking for is a translation program, I got nothing.