My galleries are one line of vertical images after upgrade

After upgrading to 3.5 (I am now 3.5.1) none of my galleries work anymore.

An example is here:
https://ustamp4fun.com/2013-leadership-display-boards/
I have about 540 photos… they were 60 per page in a neat grid with Page 1/Page 2/Page 3… now nothing.

All my settings are correct. I’ve turned off all plugins to ensure that they were not the problem. Any ideas?

https://www.ads-software.com/extend/plugins/nextgen-gallery/