how do I get a full image for an infobox?

[Graveyard666]

I want all my infoboxes to look like this:

 

 

now the pic above is a .jpg but the blue border and white text I want to make for my infoboxes but not sure how. Sure, an image header for infobox is easy, but how do you do the sides and bottom?

 

 

 

jeff