Without seeing them in person, then, I'd say that it's likely these were either signed in black and the signatures faded a lot, or the signatures were printed with the photos. But an expert would probably need to see them in person to tell.
There appears to be foxing or some other sort of staining on the photo. Perhaps it was stored in a damp basement?
These signatures are not rare enough to want to accept a condition compromised piece. Even if they are real, the desirability is really diminished if they are damaged in any way.