I have a question about mounting physical photographs in frames. Is that on topic here?
I'm doing the framing myself and I can also probably put it on Arts & Crafts, but I'm curious if it works here too, since it's kind of a presentation thing.
Yes, as long as you are framing a photograph.
However, you'll get better expertise here if the question is directly related to something about the photograph itself — either to do with matching the contents to the frame, or about the materials of the print, or something like that. If the question is about, say, making a perfect miter joint, Arts & Crafts may be better.
You note that your question is "kind of a presentation thing", so that's likely perfect for here.