Web Documents Contain an Abundance of Graphics
When reading the Web you have to deal with a large amount of graphics. You're likely familiar with ads, photos, tables, and figures; but what about icons, buttons, thumbnails, mouse-overs, or virtual reality.
Web documents often use icons to represent some sort of functionality. For instance on your desktop the icon for Microsoft Word is a piece of paper that represents the word processor.
Buttons are often used as graphical links, when you click on them you go somewhere else. For instance the graphic in the top right hand corner of this frame is a button that allows you to go back to the Graphics overveiw page.
Menu bars are a collection of buttons that usually contain key links within the site. For example the menu bar on the bottom of this page contains buttons that link to the homepage, the sitemap, the index, help, etc.
Thumbnails are small versions of graphic that when clicked on produce larger versions of the graphic. The smaller file size of thumbnails allows them to be loaded more quickly and saves space on the page for other information. Thumbnails also allow you a quick view at a graphic and the choice to view it in more detail if you wish.
Have you ever noticed a change in a graphic when you move your mouse over it? Mouse-overs are used mainly to draw attention to where your mouse is on the screen, but they also may highlight other features. For example run your mouse over the menu bar at the bottom of this page. You will notice that the button your mouse is over changes from gold to blue when your mouse is over it.
Virtualy Reality is a three dimensional graphical representation on your screen. When viewing virtual reality you move through the space just as you would in say a three dimensional video game. You might have to open doors or retrieve objects, to get the information you are looking for.