Open as Smart Object

These two commands open any image file as a smart object. The imported smart object appears in the Layers palette as the only layer.

This lets you, for example, filter your picture non-destructively (screenshot).

For opening RAW photos we strongly recommend "Open as Linked Object" command.

In this case, at any time, you can re-open the image with Edit Smart Object command in the ACR window and adjust its exposure, sharpening, or white balance settings.

NB. In cases the edited smart object doesn't update automatically, force renewing it with "Update Modified Content" command.

A video on this topic is available here.