R is for Resolution
Resolution refers to the amount of detail that can be displayed in an image.
Similar to the resolution of a computer screen, the resolution of a digital picture is measured in pixels. The number of pixels per inch combined with the resolution of the image tells you how large the image will be when printed or displayed on a screen.
- A picture which is 900 by 1200 pixels saved at 300 pixels per inch (PPI) will display an image sized at 3 x 4 inches.
- The same picture saved at 75 PPI will display an image sized at 12 x 16 inches.
To get the best printed image, images should be saved at 300 PPI and printed at 300 DPI (Dots Per Inch) to get the optimal resolution (detail) in the image. For standard web use, most monitors render no greater than 75 PPI (the exception being retina displays on some Apple devices which render a higher PPI.