I fixed it using a different code for my sidebar. I still don’t know why the conventional <div> tags wont work with image rollover. Anyway here is what I used
<a class="xbox" href="https://www.gamemunition.com/tag/Xbox-360/"></a>
instead of:
<div class="xbox"><a href="https://www.gamemunition.com/tag/Xbox-360/"><img src="https://www.gamemunition.com/images/360.png" alt="" /></a></div>