If you like me tried to create a Tiled/Mosaic Gallery in Jetpack in a localhost website you’re building, you may be surprised that this feature is no longer available starting with Jetpack 4.8 when the Settings page was redesigned.
As you may have already know, in order to use the Tiled Galleries feature starting with Jetpack 4.8+, you have to enable the Photon feature as well:
Enable Tiled Gallery from the Hidden Jetpack Menu
Thanks to Ben Gillbanks, there is an easy way to enable Tiled Galleries on localhost by accessing a hidden Jetpack Setting page:
To access this hidden page you have to add the following to the end of your localhost site URL in the address bar:
/wp-admin/admin.php?page=jetpack_modules