You should check TheNewBoston is a channel on youtube telling you how to use jQuery even from scratch.
Here is an example. I think this could help you.
$(document).ready(function() {
$('.box-img').click(function() {
$('.box-caption').slideDown('slow');
});
});
CSS:
.box-img {
width: 100px;
height: 100px;
border: thin solid gray;
position: relative;
}
.box-caption {
width: 100%;
height: 30px;
position: absolute;
bottom: 0px;
background-color: #d4d4d4;
display: none;
}
HTML:
<div class="box-img">
my image
<div class="box-caption">my caption</div>
</div>