Image dimensions are the length and width of a digital image. It is usually measured in pixels, but some graphics programs allow you to view and work with your image in the equivalent inches or centimeters. Depending on what you plan to use your image for you may want to change the image size. For example, if you are using a high-resolution digital photograph, you may want to make the image dimensions smaller for publishing to a Web page. When using a graphics or image-editing program, you will usually have two options for changing the image dimensions: resize or resample.
See also “Graphics Software Terminology” in the Quick Reference section of Webopedia.