The Two Types of Digital Images: Vector and Raster

All digital image files fall into one of two categories: vector or raster. Each format has advantages and disadvantages in different situations, so knowing the properties of each can help determine which format is the best choice for any project.

Vector

Vector files are most useful when a graphic needs to be able to handle resizing, as they retain crisp detail when scaled to any size. Vector format is an excellent choice for digital illustrations such as logos.

A vector file can be converted to a raster file, but it will permanently lose the advantages of the vector format.

Common vector file extensions: SVG, EPS, and EMF

  • SVG – web-based vector format
  • EPS – Adobe-based vector format
  • EMF – Microsoft Office-based vector format

Raster

Raster images are best for complex images like photographs, and are more likely to be a widely compatible file format (such as JPG). However, raster images lose detail and become increasingly blurry when enlarged.

Although a vector image can be saved as a raster image, it is not possible to convert a raster image into a vector image. Raster files saved as vector file formats will still be raster files. Most images on the web are raster files.

Common raster file extensions: JPG, PNG, and TIFF

  • JPG – compressed raster format, often used for photos
    • Best for web use
    • Small file size
    • Universal – compatible with most software
    • Most images on stock photography websites will be downloaded as JPG files
  • PNG – raster format good for illustrations or icons
    • supports transparency, unlike JPG
    • Best for web use
    • Small file size
  • TIFF – raster format that is best for high-resolution printing
    • Great for professional print use, especially when preserving crisp image detail is important
    • Large file size