Tilled Gallery problem

Hi

I have a problem with a Tiled Gallery on my blog.
It was working properly but today I noticed the size of the Gallery is bigger than the width of my blog. The Thumbnails are not fitting in a screen.
I checked and the width is set up in my Theme function.php file
“if ( ! isset( $content_width ) )
$content_width = 720;”
And I tried to install a Content Width Plugin as well but it didn’t help.
Please could you advise regarding that problem.

Thanks
Shamack

https://www.ads-software.com/plugins/jetpack/