Width of single thumbnail gallery

Hi Guys,

This might be a stupid question, but it bothers me.

I have created a “Single Thumbnail Gallery” and set it width to 648 px (the width of my content column. However, the thumbnail is presumably 640 px in width (http://screencast.com/t/SJMZgxyKr). Even if I set width to 700 px, is doesn’t get wider.

I suppose it has something to do with borders or padding or something similar.

I am not into coding too much.

Coul you help me fix it so that the thumb is the exact width of my content column and stays this way even after I update the plugin to newer version?

Thank you

https://wordpress.org/plugins/foogallery/