Mouse over darken & add text on link images in galleries

I have just figured out how to do my image galleries with all those cool options (circles etc) on my static front page. I have a plug in that enables each image to link to a blog post. What I’m trying to figure out is how to get the images to darken and display the related blog post name right over top (not under as a caption) when the reader mouses over it.

I have been at this for days now and can’t figure it out :/

Example, not my site: http://lisajohnsonphotography.ca/