helping you get your JSworking - had to change around a couple things

Some things that I changed to get this working:

1. $(document).ready(function(){}); --> you need this at the beginning of your JS file. This is stating that when the document is ready do whatever is in the function. 

2. $(this).find(".image-overlay") --> this basically is saying the item that triggered the event (in this case was $('.wrap_mouseover')) find the element .image-overlay and show or hide it. This allows for the hover to only be on one of the items instead of all the items.

I changed some other shit but i think you probably already know all this. So it's just for clarification.