Determine what the image size should be. Pixels Dots Per Inch Inches When dealing with graphics files there are 3 properties that go into determining the resolution or size of a file.
Pixels Pixels: The exact number of 'dots' both horizontally and vertically that make up the file. This is the actual resolution of the file. DPI and Inches affect only the size of the image as it is displayed or printed, but the actual pixels is finite in a bitmapped file.
Dots Per Inch DPI (Dots per inch): The number of 'dots' or pixels per each inch of a printed or scanned document.
Inches The actual size measured in inches (either printed or scanned) of an image.