Help with NextGen-Gallery

Hi there

I just started using the NextGen Gallery plugin and would like to how I can add a background color or frame border on the blow up image when you click on the thumbnail? I looked online for tutorials but there was nothing I can find so it leads to opening this thread here.

I think it has something to do with the CSS but unsure where to start unless if worse comes worse then I might have to go through style and test it from there.

Would much appreciate your help in anyway.

Many thanks in advance
CHEERS 🙂