>>>Also, what about the photo credits (often-but not always-on side of the pictures, at 90 degrees)?

Why not move one step further and enable scribus (as an option in the context menu) to read the "Copyright" field from the IPTC metadata (or show all ITPC data and select a particular field) in an image file and create the copyright frame automatically? This could probably done by a script, but to have it available somewhere would be extremely useful in many environments.