i have a fabric-covered bulletin board and i display photos on it by pushing pins in at an angle right next to the edge of the photo, so the pin doesn't poke through the photo itself, but the ball of the pin is holding the photo against the board. i usually put three pins in at offset locations along two or three edges of the photo.
you don't have a to buy a bulletin board to do this. get some large sheets of cardboard for free. furniture stores are great for this because the cardboard is clean and they have huge pieces with no folds or seams in them (like, a mattress box). put two or three layers together and tape them with packaging tape or duct tape. staple on your fabric, and you're good! you could also do the criss-crossed ribbons over the whole thing to tuck photos into, but i prefer a tidier look. smaller bulletin boards will be easier to hang, and you can do a set of three or four if you want a grouping and/or a larger display area, or you could go super huge and just set it on the floor or a side table and let it lean against the wall, without having to mount it at all.