typically i suggest alMOST all questions newbies might ask...
have been asked and answered dozens (if not 100s) of times,
so go search and read the archives.
but HANgING art (especially photogs) has not been asked about that i recall...
except in terms of 'framing' and wall attachment methods.
so here are THREE suggestions
till some1 knowledgable on the issue posts...
1. for really really precious photos consider some sort of air/moisture sealed enclosure, that is also UV resistant.
photos can also be sprayed with something? that makes them moisture resistant...
rv walls DO change temps quickly and condensation is a REAL issue near windows,
and on the NAKED international inner skins this is even a bigger issue.
i would NOT hang print/photo art over the windows, with or without the curtains/blinds closed, that's a bad idea.
2. make a portfolio of the stuff you wanna look at and flip da pages occasionally.
this could be kept in more moderate space inside the stream,
and pulled OUT for looking and showin'
3. SCAN or digitize (if not already done) the photos and use a BIG led/lcd screen to display
isn't that what the cool rich folks do now (vis a vis b. gates) ?
high quality photo paper and professional developing is PRETTY durable stuff, but do ya wanna risk it?
((btw i've had 2-3 BIG photos hanging in the SHOWER ROOM at home for nearly 20 years, they still look great))
but in the stream EVERYTHING art-ish hanGing on the walls is SEALED or laminated.
now that we've dealt with the ODD BALL question...
alMOST everything related to sizes, full timing and the simple life rv myth has been posted, so go read...