On a 56K modem (yep, theyre still around), it would take forever to load this page. Plus, it kind of hurts my eyes. If youve got load-intensive graphics or other technology that takes a long time to load, youll have lost a good part of your audience.
No one wants to wait around forever while a site is loading. Even if youve got a site with great content, if the graphics are dragging it down, youll have lost your audience. Theyll just be using the Back button to quickly find another site that wont take forever to load.
A good rule of thumb is to only use graphics that are relevant to your sites purpose, and aim for a file size that is 12 KB or smaller. If you must include an image that is larger than 12 KB, then use a thumbnail image.
In the context of search engine optimization, load-intensive graphics will hinder search engine spiders, since spiders primary food is content. Use images sparingly, and instead, work on adding relevant content that will attract both users and search engine spiders.