change img src on click

Your second attempt is correct. Here is the working jsFiddle: http://jsfiddle.net/MEHhs/

So the code should be:

html:

<div id="picture_here">
     <img src="http://www.sbtjapan.com/img/FaceBook_img.jpg" id="picture"/>
</div>

<div id="about">
     <div id="mtl">Mtl</div>
</div>

<div id="about_2">
     <div id="contact">SF</div>
</div>​

js:

$('#mtl').click(function(){
    $('#picture').attr('src', 'http://profile.ak.fbcdn.net/hprofile-ak-ash3/41811_170099283015889_1174445894_q.jpg');
    });

I’ve added some existing images found on google.