Digital Commons at Penn State

To put it simply, the photo was taken at a high resolution setting on the camera. When you open it in an application such as Photoshop, it may look pretty large -- you may even have to scroll to see the whole photo. The file's physical dimensions, however, may only be something like 3"x5", which is what the printer will output. A lower resolution setting will result in a smaller size on the monitor, but the same physical size when the photo prints. Its quality will not be as good as a photo taken at a higher resolution setting, however.

An image's resolution is measured in dots per inch, or pixels per inch in the digital realm. Since a monitor never displays more than 72 dpi (dots per inch), photos that will never be used in print (such as for the Web or PowerPoint) are better saved down to 72 dpi from higher resolutions. You'll have a smaller file size and the files will load more quickly.

To see a file's physical size and resolution, open it in Photoshop and under the "Image" menu, go to "Image Size...". It will bring up a window that will allow you to view and adjust the photo's physical size and resolution.