<img id="myimg" src="userimage.png">
<script src="https://ajax.googleapis.com/ajax/libs/jquery/2.1.4/jquery.min.js"></script>
<script>
$(document).ready(function() {
setInterval(function() {
$("#myimg").attr("src", "userimage.png?" + new Date().getTime());
}, 2000);
});
</script>