There are many ways to do what you want to do. Here is a tutorial that will show you how to get it done. Just alter the css to fit your needs
http://webdesignandsuch.com/create-overlay-on-image-hover-jquery-css3/
as far as linking. You can use WordPress code for that. Such as
<a href="https://wordpress.stackexchange.com/questions/81732/<?php the_permalink(); ?>"><img src="your image with overlay"></a>