I am a writer and photographer, an enthusiast for Carl Zeiss lenses and the late, great SX-70 Polaroid camera and film. I have been inspired by Henri Cartier-Bresson's idea of the "decisive moment"--instinct and chance, as opposed to staging. I do not own a digital camera, aside from the iPhone6s+.
On this site, you can purchase quality prints of various sizes and also a nice, all-cotton T-shirt emblazoned with a photo. Just a couple suggestions. With the Minox Spy Camera images, don't go beyond a 5 by 7 inch print, because the negatives were so tiny. With the Polaroid SX-70 images, go to the "other sizes" section, and chose either 5 by 5 inches or 8 by 8 inches, nothing larger. The original SX-70 positive image was 3 inches square and one-of-a-kind. It was not created to be enlarged and duplicated.
With most other images, a nice print size is 8 by 12, which roughly corresponds in proportion to a 35 mm negative or transparency. Ditto 10 by 15. In addition, you can choose to crop the image the way you want at check-out. The whole process is not difficult or intimidating. It's intuitive. Often you will see what look like duplicates, but they are not. I have changed the color, brightness or hue of the same photo, which means it is a separate photo.
Occassionally, a print size of 4 by 8 inches will be appropriate when I have already narrowly cropped the image. You can find this odd size in "other sizes" when choosing the print at check-out.
Of course, you can just look around. Cheers. This site is always under construction.