The last column is missing on the starting page

Hello,

if I start the Homepage (www.silkeritzert.de) with a desktop computer, the last column is missing and only white space is shown.
How can I rearrange the gallery that it will not be so asymmetric?
The layout in the responsive design with a tablet or mobile phone works very fine.

Thank you very much for your support.
Martina

The page I need help with: [log in to see the link]