List 3 x 33% <li> not going into <ul> 100%

For a website I am working on the gallery page which you can see here. But for some odd reason does three <li’s> from 33% not fit in the parent <ul> as you can see. I even made the <li’s> 30%, but it’s keep giving me two columns instead of the desired three? What am I overseeing?

Thank you in advance!

You mean the gallery images? Which browser/OS? Firefox and Chromium on Ubuntu are both showing three columns:

Hi, donboe. It looks like you are floating the list items.

You can look at the <ul> example in this post and see how it handles images in list items that are inline-blocks instead of floats.