In general, the resolution of your photos should be as high as possible for all photo products in order to achieve optimal results. When ordering digital photos, you will be shown a quality message upon uploading the images if the resolution of an image is critical or too low. You can still have low resolution photos developed, but they may have poor image quality.
Tip: For optimal print quality (300 dpi), your digital photo should have the following resolution (in pixels) or sensor resolution (in MP) in a 2:3 ratio:
Format 9 cm 1050x1600 pixels or 2.0 MP
Format 10 cm 1200x1800 pixels or 2.2 MP
Format 11 cm 1350 x 2025 pixels or 2.8 MP
Format 13 cm 1500 x 2250 Pixel or 3.4 MP
Format 20 cm 2400 x 3600 pixels or 10 MP