Recommended Resolution Guide

 

When ordering a print you should pick a print size that is appropriate to the resolution of your image for best results. If you are seeing a warning for one of your images, try ordering a smaller print size. However, as long as your images meet the above/close to the approximately specifications, it should be safe for you to go ahead and place the order despite the warning. 

The generally accepted value is 300 pixels/inch. Printing an image at a resolution of 300 pixels/inch squeezes the pixels in close enough together to keep everything looking sharp. In fact, 300 is usually a bit more than you need.