how can I reduced the size of space between thumbnails?

[jopat]

I did look for an answer with search, but didn't find one. what I mean is I want to move all the thumbnail close to each other, so which part of CCS I have to change?

thank you
patrick

[erichmangl]

when you edit your gallery you find "cell spacing"

[jopat]

Thanks erichmang, I thought it has to be done on changing CSS.