Some digitizers, especially flatbed scanners, claim high scanning resolutions that are actually achieved through interpolation. Here is a 72 dpi image. Here is the same image after being reduced to 36 dpi. Here , the resolution has been interpolated back to 72 dpi. Image Size Image size refers to the height and width of the image, measured in inches, centimeters, dots, or any other unit of measure.
Image size is a little tricky to grasp due to the fact that the resolution of an image can vary.
For example, it is not of much help to know that an image is 3 by 5 inches if you do not know how many dots per inch make up the image. And, an image of 3 by 5 inches at 100 dots per inch contains the same amount of image data as does an image of 6 by 10 inches at 50 dots per inch. Alternatively, if the image size is measured in dots or pixels, then you know exactly how much image data exists because a 300 pixel by 500 pixel image contains 15,000 pixels no matter how many pixels you designate per inch. Now, when talking about color depth, we are essentially referring to how many different colors can exist within a particular image. The actual colors that are used within an image make up the color palette for that image.