<!DOCTYPE HTML>
<html>
<head>
<script src="http://ajax.googleapis.com/ajax/libs/jquery/1/jquery.js"></script>
</head>
<body>
<div id="example">
<img src="one.png" />
<img src="two.png" />
</div>
<script>
function find(imid) {
var img = $('#'+imid+' img:first');
alert(img.attr('src'));
}
find('example');
</script>
</body>
</html>