As someone who likes to make minis, I need to have photos that are smaller than 3x5 much of the time. Cropping 3x5 or 4x6 photos down to the size I needed didn't work because I lost too much of the picture detail that I wanted to scrap. I develop my photos at Costco most of the time, but the smallest print you can make is a 4x6, unless you buy a sheet of four wallets for 26 cents more, and even then all four wallets are of the same photo.
I discovered a program called Photosheet that can be downloaded for free here www.photility.com
Here you can select what size sheet you want to print, 4x6, 8x10, etc. and then decide how many pictures you want to add to that sheet, all of the pictures can be different if you want! Then you just save the file and upload it to your favorite photo printing site. One of my favorites to print is four 2x2's on a 5x7 sheet. I use this program for every mini I make, LOVE it!