I saved all proof and civil documents, that were required, under I-130 as pdf so I can go back to it, if needed, everything pertaining to it is tied with this filing. Concerning pictures and gift receipts, much is really not needed. You can include a pic and conversation in 3 points of the relationship beginning , the engagement and, now marriage with 2 pics and 2 text noting on them who is who and brief description what is going on in that pic.