Take a look at your fabrics and see what size of square you need to capture the image with a 1/4 inch seam allowance all around. 5 inches seems to be a good size for squares but I have also seen minis that are purse size quilts with tiny 2 inch square I Spy’s for keeping children amused at church or similar. Another option is a match I spy where there are 2 images the same that a child can find. Match I spy’s are also a good option if you have a limited number of conversation prints to work with. Have fun!