I recently made a memory quilt for my son and daughter-in-law's anniversary. It had pictures of , what else, my granddaughters. I used regular 4x6 snapshots. I put them in my printer and printed them on sheets of paper that had fabric stuck to them. I bought the sheets at my quilting shop. The ink from the printer inbeds itself into the fabric and does not wash out. I could enlarge or reduce the size to fit my purpose. Sorry, I can't recall the name of the product. After printing, you just peel the cloth off of the paper. The clothis your quilt square. It comes in white and beige. It cost was about $2 a sheet. Hope this helped.
I made one about 25 years ago using the heat transfer method. The pictures soon washed out.
Ruth