Resize constrain images

[Todd Anderson]

I need to display images a 600x400 or 100% of the table they are in.
It appears that  this code is where you would set the image size but it's not affesting it.
\$(function() {
      \$('#slides').slidesjs({
             width: '600',
          height: '400',
          play: {
          active: true,
          auto: true,
          interval: 4000,
          swap: true
          }
      });
    });
Any help???