Wells Template Image Description in Sidebar

Hello 

I am trying to set up a new site and create a gallery similar to the below (not my site), where the description appears in the sidebar (Image attached, caption highlighted in red square) but can't find the option to do this in the wells template. 

https://sionmarshallwaters.com/forest-coal-pit

Any advice on how i do this greatly appreciated. 

Thank you 

Have you achieved this yet?