No it is not bad form to ask anyone. If a provider has an issue being upfront and honest about her photos, it says something. If she says the photos are over a year old, then of course you have a right to ask if she something a little more current. Perhaps her answer will be she has not changed at all since those photos, then thats fine and you now know what to expect.

Very respectful of you to even ask if that's ok! Asking for additional pictures generally is at least annoying for me, but usually that's because the vast majority of guys who ask for them are trying to get additional pics for free and not actually interested in booking a session.

However, especially if you've already expressed genuine interest, inquiring whether the pictures are current and asking for a current selfie or something like that seems fine to me. I've done that for clients. As long as you don't launch into the conversation immediately with that. Most ladies are trying to avoid time wasters I think. HOWEVER-if a girl wants to keep her face hidden for discretion, that's worth respecting.

Lots of girls post on sites like twitter and have selfies and more recent photos than websites and ad sites. However, once a ways back, I wondered if a provider I saw once before had changed since I saw her last. The pictures were the same. I got a annoyed response that if my seeing her is contingent on her posting new photos she wasn't interested. I never tried again. LOL.