Gallery view setting for 49

I use to see 49 people in gallery, now I only see 25...One of the post suggest the following: Please check the option to display 49 in the gallery view on the Settings -> Video window. 

When I am on my account page, and go to settings under "Personal" I cannot see anything related to Video window.  Where do I find this setting? On my account?  When in a meeting?

Thanks....