What Are Raster Graphics?

Date First Published: 3rd December 2023

Topic: Computer Systems

Subtopic: Computer Software

Article Type: Computer Terms & Definitions

Difficulty Level: 5/10

Learn about what raster graphics is in this article.

Raster graphics, also known as bitmaps, are computer graphics made up of tiny rectangular pixels arranged in a grid formation that can represent an image. Every pixel displays a unique colour and all of these coloured pixels make up an image. They are most commonly used for digital photographs, but can also be used for illustrations and logos.

Raster graphics and vector graphics are the two most common graphic types used to digitally represent 2D images. Vector graphics are different from raster graphics in that they consist of points and paths and mathematical relationships that connect them to create an image.

Advantages and Disadvantages Of Raster Graphics

• They allow for detailed and high-quality digital images as long as files are exported at a high resolution and displayed on a high-resolution screen.
• They are usually easy to edit and are widely supported by most software.
• They can capture detail and variations of light, colour, and shadow that vector graphics cannot.

• They are often larger in size than vector graphics. Their large file sizes can slow down page loading speeds on the Web and take up a lot of disk space.
• They become blurry when enlarged. Unlike vector graphics, when images are zoomed in or resized, they often become blurry and lose their quality. This makes them less suitable for images that need to appear in a wide variety of sizes.
• They are harder to edit and manipulate and can be affected by compression, noise, artefacts, and loss of data, which can harm the quality of raster graphics.

File Size

The file size of a raster graphic depends on the resolution of the image and the colour depth. A higher-resolution image has more pixels and requires more disk space to store and a higher colour depth means that more data will be stored.

Raster graphics are usually stored as .jpeg, .png, .gif, .tiff, and .bmp files and the file size also depends on the amount of compression used. For example, a large raster graphic stored in the uncompressed .bmp format will have a much larger file size than the same raster graphic saved as in the lossy JPEG format. The image compression algorithms greatly reduce the file size of JPEG files, speeding up file transfers and leading to less bandwidth needed to transfer and download digital images.

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