WebP can drastically reduce space requirements for files. WebP is not supported on all browsers or versions. To learn if these settings are appropriate for your setup, visit Can I Use.

When saving bookmarks, convert them to WebP.
When generating covers, convert them to WebP.
  Location where bookmarks will be stored. Bookmarks are source files and can be large. Choose a location with adequate storage. Directory is managed; other files within directory will be deleted. If Docker, mount an additional volume and use that.