#dwqa-question-content-editor{
font-size: 125%;
}
.form-submit{
margin: 25px 0;
}
<a class="fancybox" href="image_big.jpg">
<img src="image_small.jpg" width="100" height="100" alt=""/>
</a>
<script type="text/javascript">
jQuery(document).ready(function() {
jQuery(".fancybox").fancybox();
});
</script>