Cardboard Letter of your choosing
I had my husband paint a base coat on the B before I got started so that the sides and anything else that showed through between the pictures would be covered. I chose a paint color that I knew would go with my MIL's home's color palate.
Once it was all painted, I laid out all of the pictures and tried to figure out where they would all go. Please disregard my crazy unorganized
Once all of the pictures were placed appropriately, I started trimming the photos down to size. This takes a while and it starts to feel a bit like Tetris to get everything to fit how you want it to.
Once I was happy with the locations, I started mod podging everything on. I did the backs and edges first.
Once everything was glued down, I went over all of it with the mod podge to guarantee the photos would stay in place as I desired.
Once it all dries, you have an inexpensive and meaningful gift to present to someone special. This once went to my MIL and FIL for their anniversary this year.