<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
 
<style type="text/css">
.clickimage{width:200px;border:0;cursor:pointer;}
</style>
 
<script type="text/javascript">
 $('#bilderzoom').click(function() { 
 if($(this).hasClass('clickimage')) {
 $(this).animate({'width: 200px'}, 'slow');
 $(this).removeClass('clickimage');
 } else {
 $(this).animate({'width: 800px'}, 'slow');
 $(this).addClass('clickimage');
 }
 });
</script>
 
<img id="bilderzoom" class="clickimage" src="http://www.bilder-hochladen.net/files/big/kr03-3f-da4f.jpeg">
 
 

<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.7.2/jquery.min.js"></script>
 
<style>
.bilderzoom{width:200px;border:0;cursor:pointer;}
</style>
1. Bild <img class="bilderzoom" src="http://www.bilder-hochladen.net/files/big/kr03-3f-da4f.jpeg">
2. Bild <img class="bilderzoom" src="http://www.bilder-hochladen.net/files/big/kr03-3f-da4f.jpeg">
 
<script>
    $(function(){
        $('.bilderzoom').toggle(
              function() { $(this).animate({width: "800px"}, 'slow')},
               function() { $(this).animate({width: "200px"}, 'slow')}
        );
  });  
</script>