about width of thumbs_list

[u2popart]

Hello all
I bought a template, I pretty design changes, qq codes .. but I have a pb when I want to make variations of products, which adds a menu to the right of the picture, my thumbs images are shifted down and are no longer side by side. look on this page http://u2popart.com/new-york/1-love-design-new-york.html

I found the solution on the page itself. html, it only calculates the size of img (70px multiplies by 2 = 140) but it does not take into account the margin of 10px Finally I think it's ca the problem!

With firebug I correct this problem by putting on so 160px thumbs_list li

but I do not know or modify it to see the display heads on my pages.
Thank you for your help