What is pixel resolution?

What are pixels?

A pixel is defined as the smallest element of a digital image. Let's think of an image as a matrix of a lot of tiny boxes, where each box has a fixed color intensity. We can refer to each of these boxes as a pixel.

Pixel resolution

Pixel resolution is the total pixel count in a digital image. It is usually written as the total number of horizontal pixels by the total number of vertical pixels. For example, a common resolution is $1920\times 1080.$It means that an image has 1920 vertical pixels and 1080 horizontal pixels.

Different notations

Pixel resolution can be written in various forms. For example, a pixel resolution of $3840 \times 2160$ is also referred to as 4K.

Megapixels

Another common term used to refer to pixel resolution is megapixels. It is the total amount of pixels in an image divided by 1 million. For example, a $1080p$ image has $1920\times 1080 = 2,073,600 = 2.07$million pixels. Hence, it has a resolution of approximately $2.07$ megapixels. This terminology is most commonly used when dealing with digital cameras to explain the maximum resolution they can capture images at.

Aspect ratio

Aspect ratio refers to the ratio of the total number of horizontal pixels to the total number of vertical pixels. For example, a $1920 \times 1080$ image has a ratio of $16:9.$This term is most important when dealing with image upscalingUpscaling is increasing the resolution of an image by duplicating pixels and applying some image processing. or downscalingDownscaling is the process of reducing the size of an image by reducing the amount of pixels it has.. It ensures that the image does not look stretched or shrunken.

Compression

Image compression is another phenomenon that is linked to pixel resolution. Images are compressed to reduce their size. To do so, we need to reduce the number of pixels in the image. Hence, compression can be done by scaling down the image and reducing its overall resolution.