This article explains Smart Objects in Photoshop and tells the different types of smart objects & how to create, edit, and convert them.

You can add pretty much anything you want, too. Photoshop Secrets suggests using this feature to make it easier to add and edit smart objects: I use Smart Objects quite a lot in my work.

Prepare the photo In Photoshop, choose File > Open as Smart Object and navigate to the soon-to-be-painterly photo.

Smart Filters Filters may also appear to be missing when using Smart Objects in Photoshop.