At what resolution do you need photos for printing?

For best quality results photos should contain enough pixels to be able to be printed: a minimum of 300 ppi (pixels per inch) is the desired size for print. For example a photo that needs to be printed at a desired size of 1 inch square would need to be at least 300 pixels wide by 300 pixels high. N.B. Some applications mislabel the term ppi as dpi.