Hi David - welcome!
Unfortunately, the ability to view attachments from within the app is a feature that is not yet available. A lot of people would like to see this, so if you want to add your vote to the list to accelerate its development, see this thread:
Also, one user found a workaround to open Bitwarden attachments seamlessly in iOS without having to perform a manual download first - the instructions are buried in that same thread, but here is a link directly to them, in case they are of any interest to you:
Regarding the difference in photo filenames, that’s a known Apple quirk. I couldn’t find it right away, but I remember reading somewhere how to overcome it - I think it was on the Apple support forums. Sorry that I couldn’t locate that for you.