If you embed a Gallery that uses a Theme with the Share button feature enabled, you will be able to share your Gallery on social media sites.
To adjust these Share button settings, head to Themes before selecting Edit in the Theme of your choice. Now simply select the Sharing option from the left-hand-side menu.
Similarly to when you share a SmartFrame on social media, only a small thumbnail and a title and/or description will be visible in your post. The title and description can be added when you create your Gallery in the Social media setting section, while the thumbnail will always be the first image that appears in the Gallery.