The radio buttons do not have to be visible, you can hide them and just have a label (which is your image) activate the associated radio. I put together an example.
<input type="radio" name="color" value="black" id="black">
<label for="black">
<img src="black.png" alt="black">
</label>
You can use CSS to display a border around whichever image is selected, and if you add a class to indication the current one, use a different border to indicate the current item. In my example above, the selected item has a white border, the current has a yellow border.