Good practice in the use of graphics helps to make Web pages more accessible. File size Large, slow-loading images are likely to irritate users, particularly if they are inline images which can delay the loading of the whole page. Keeping down file size to no more than is necessary speeds up loading of pages, comforting both user and network manager. This means that the density of the image will be gradually built up as loading of the page progresses. It helps if they appear to blend in with the rest of the page.
Transparent backgrounds help to make images look as if they belong.
Low fidelity monitors can make viewing of images difficult. Read also this article in MacUser about Web Color Wizardry . There are several good tips. Alternatives to graphics Providing alternatives to images provides portability and flexibility. Use 89a and interlace the pictures when they are large.