title: How to preload my nav bar's graphics
body: <p>I created and coded my own css navigation bar (inspired by apple, if that helps you visualize), that means i have dynamic buttons with 4 states that i manage with a css stylesheet.  I only have two graphics, one with the button states, and another with the stylized "text".</p>
  
  <p>However, i'de like to make it so that the nab bar's graphics are preloaded in my webpages. </p>
  
  <p>1) is this possible ?</p>
  
  <p>2) is it useful ? </p>
  
  <p>3) if yes to both questions what would be the code ?</p>