Skip to Main Content
homepage homepage

Images: Raster vs. Vector

Raster vs Vector

Raster images, or bitmaps, are composed of a fixed set of tiny dots or pixels. These kind of images are produced with scanning or photographing an object. Since raster images are pixel based, they are resolution dependent. The number of pixels that make up an image as well as how many of those pixels are displayed per inch, both determine the quality of an image. As you may have guessed, the more pixels in the image and the higher the resolution is, the higher quality the image will be. Some of the basic file types include JPG, GIF, PNG and TIFF.  See the link below for a more complete list of raster file types.

Vector images are composed of mathematical equations where lines and curves (or paths) make up graphic shapes, images, and text in XML format. One of the greatest things about vector images is that you can re-size them infinitely larger or smaller, and they will still print out just as clearly, with no increase (or decrease) in file. Thus, they are resolution independent.  SVG and EPS are vector file types. See the link below for a more complete list of Vector file types.

Raster (or bitmap) images are generally what you think about when thinking of images. These are the types of images that are produced when scanning or photographing an object. Raster images are compiled using pixels, or tiny dots, containing unique color and tonal information that come together to create the image. 

Since raster images are pixel based, they are resolution dependent. The number of pixels that make up an image as well as how many of those pixels are displayed per inch, both determine the quality of an image. As you may have guessed, the more pixels in the image and the higher the resolution is, the higher quality the image will be.

For example, if we scale a raster image to enlarge it, without changing resolution, it will lose quality and look blurry or pixilated. This is because we are stretching the pixels over a larger area, thus making them look less sharp. This is a common problem but can be remedied by using raster image editing programs such as Photoshop to change resolution and properly scale images.