Examples of file size and type - Images for the web - Web Team - University of Canterbury - New Zealand

Examples of file size and type

Examples of file size

This photo is 105KB. It hasn't been optimised.

This version has been optimised to 16KB. There is very little loss of quality.

This version is more compressed at 10KB. Some loss of quality is evident, especially around the edges of the trees and grass. The quality is still ok.

At maximum compression, the file size is 5KB but the quality is poorer.

This version has been cropped, removing unnecessary parts to the original photo. It is physically smaller but still big enough to view clearly. Compressed it is 8k, with only slight evidence of compression on the edge of the trees.

Which image is best?
  • The image at 101k is too big
  • The image at 16kb is acceptable. If more than 2 images of this size are to appear on a page, ideally more compression should be applied
  • The 8k image shows a good balance between quality and image size
  • The 5km image has lost too much quality
  • The cropped version at 8kb is best. The unnecessary parts have been cropped out and the image quality is appropriate
  • Balancing image quality and file size is a fine balance. Each image will be different
Examples of image formats - jpeg and gif

This photo is 9.5k and has been compressed as a JPEG (.jpg) file. Image quality is good. Gradations in colour and tone are visible because JPEG is the best file type for photos.

This photo is 16k and has been saved as a GIF file. The photo is 'posterized' into areas of flat color. Subtle gradations and some tones are lost. File size is more than twice as large as the correct JPEG (.jpg) file.