The size of the low resolution files is limited to 1255 x 837px / 72dpi / 3MB. What this mean is that the low-res photos are most suitable to be displayed as digital products (either as small pictures on the web or social media networks).

They are not ideal for printing large however the prints should look OK when printed to sizes up to A6 ~ 105 x 148 mm ~ 4.1 x 5.8 inches. If you require quality photos printed any larger than that, you may need to use the high-res option.