The image resolution is a term that says something about how much image detail an image can hold. The term is most often used in relation to digital images, but is also used to describe how grainy a "film-based" image is. Higher resolution means more image detail. For digital raster-images, the convention is to describe the image resolution with the set of two positive integer-numbers, where the first number is the number of pixel-columns (width) and the second is the number of pixel-rows (height). The second most popular convention is to describe the total number of pixels in the image (typically given as number of megapixels), wich can be calculated by multiplying pixel-columns with pixel-rows. Other conventions include describing resolution per area-unit or resolution per length-unit such as pixels per inch. Below is an illustration of how the same image will appear at different resolutions.
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