Replace Content )f Source Attribute

HTML

<div class="div1">
    <p>this is modified</p>
    <img src="https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xtf1/t31.0-8/12605316_995354503864218_3990892340781902470_o.jpg" />
</div>
<div class="div2">
    <p>this is not modified</p>
    <img src="https://fbcdn-sphotos-e-a.akamaihd.net/hphotos-ak-xtf1/t31.0-8/12605316_995354503864218_3990892340781902470_o.jpg" />
</div>

JavaScript

//modify src URL to pull in different image size

$('.div1>img').attr('src',function(i,e){
 return e.replace("s.jpg","o.jpg");
})

// $('.div1>img:contains(s.jpg)').each(function(){
//  $(this).html(
//    $(this).html().replace('s.jpg','o.jpg')
//  );
//});

  // get image dom element
//var img = document.getElementById('imageId');

  // update src
//img.src = img.src.replace(/s.jpg/, 'o.jpg');