I think my question is pretty understandable with this image : (Seems like I can't post images for now... Here's the link)
[http://i.imgur.com/xpCaj0U.png](https://i.imgur.com/xpCaj0U.png)

I'd want to have pictures in each corners with just a 2px borders taking the whole screen.
Seems like a dumb question to me but didn't find a solution since I'm a beginner. Anyways I'd like to know the best way of doing this, considering that I'll maybe put gif's animating on hover.

Thank you in advance for you help :)