What is Image Resolution?
The resolution of an image refers to the density of the pixels (picture element or color grid or tiny color square or printed dots) that make up image or digital image or graphics on a web page or photos from a digital camera. Image resolution determines the number of pixels that a digital image can contain and as such the depth of quality and size of the file.
Once take a picture with your digital camera or scan an image, it becomes digitalized and made up of hundreds of thousands of pixels. Pixels are nothing more than very tiny colored squares. If you increase the magnification of any image you will eventually see the individual square pixels that make up the image.
undefinedThis is a close up of a low resolution image. Notice the squares – these are pixels (Original Dimensions of this image is 2592 X 1944).
Image Resolution is measured by the number of pixels per inch- PPI, for-on screen images. The more pixels there are in an image per inch, the better the quality and the higher the resolution. The higher the resolution, the larger the file size is. For printing, resolution is measured by the number of dots printed in a linear inch-DPI. DPI is often used to describe PPI and vice versa.
When an image has a high resolution, the pixels are small so more of them can be packed together creating more detail. Smaller pixels produce a smooth, high quality print. Because there are a high number of pixels the image file size is also large. You can see from the simple example below is an illustration of how the same image might appear at different pixel resolutions, if the pixels were poorly rendered as sharp squares.
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An image that is 2592 pixels in width and 1944 pixels in height has a total of 2592×1944 = 5,038,848 pixels or 5.0 megapixels. One could refer to it as 2592 by 1944 or a 5.0-megapixel image.