// Slider by ILyeS  
  function block_off(){$('.block img').hide()};  
  function block_on(a){$('.block img:'+a).fadeIn(300)};  
  block_on('eq(0)')

<div class="block">  

  <img src="url">  
  <img src="url">  
  <img src="url">  

  <div>  

  <a href="javascript://" onclick="block_off();block_on('eq(0)')">1</a>  
  <a href="javascript://" onclick="block_off();block_on('eq(1)')">2</a>  
  <a href="javascript://" onclick="block_off();block_on('eq(2)')">3</a>  

  </div></div>