I think if we stuck to non-sexual pictures, it wouldn't contribute to a decline in class (at least, as non-sexual as pictures of sex toys can be--by which I mean no nudity, no penetration, absolutely clean toys, etc).
I think that the ability to add pictures in cases of discrepencies or for explanation purposes would be helpful. For example, I just finished a handcuff review in which I explained how I had hooked them together to get the strongest attachment. I could have taken that bit out and just replaced it with a small picture of my hands hooked together.
There's no reason for anyone's anonymity to be compromised, and I'd even argue that pictures shouldn't include the reviewer's face at all because it's not relevant--just whatever discrepancy or demonstration you want to show with the toy in a non-pornographic environment.
If this gets implemented, pictures could just be checked out when the review is approved for publishing. If people start trying to abuse it by posting porn, then their ability to add pictures (or everyone's ability to add pictures) can be removed.
If nothing else, I think it's worth a shot because sometimes pictures are easier to explain things with than words.