Is there going to be an appeal?

Appeal won't be possible. This already was a ruling by Germany's highest court. Going by the linked summary there are two cases to distinguish:

• Photographs by the museum are under "Lichtbildschutz" (50 years post publication, not full 70pma), because the photographer has multiple options concerning several parameters. (This verdict seems wrong, because there aren't the mentioned parameters are fixed in repro photography. Again the BGH shows its incompetency regarding photography. But it is as it is.)
• Photographs by a visitor are a contract violation. The photographer is liable to restitution. In this case by not uploading the images any further. There is nothing about redistribution by third parties, though.

 - Sebastian