Good graphic design can make or break a website. However, often graphic design is considered before the architecture of a website - with usability suffering as a consequence.
It's vital that graphic design should be addressed only after usability has been satisfied. This places constraints on graphic design but this should be thought of as an opportunity to innovate within the limits imposed.
Web pages impart information primarily with text so text shouldn't be overshadowed by images. Except in the case of images that illustrate, most images are there to enhance the user's experience by making text content less bland and this should be remembered.
Animation
Animated web graphics are normally either GIF or Shockwave (Flash).
GIF Animation
GIF animations are constructed using separate graphic frames that are displayed at intervals on top of each other. One drawback is that the resulting file size may be very large and this slows download.
Shockwave Animation (Flash)
Shockwave animation is far more sophisticated than GIF and also requires much smaller file sizes.
When considering animation ...
Some users are so irritated by animation (especially Flash) that they will exit a web page as soon as they see it.
Don't animate graphics just for the sake of it. Animation grabs attention so should only be used if it has a purpose and you really wish users to concentrate on an item at the expense of ignoring others.
Avoid multiple animated graphics on a page - it's confusing and just looks unprofessional.
Avoid using a full sized animation as the intro page to your site. If you do then there had better be a really good reason and you should provide a link that allows users to skip the intro.
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