Preview Pane > Document Properties Tab
The Document Properties tab displays general properties of the selected document. These properties are the same that you would see if you opened the Document Properties dialog, only they are not editable from this location.
In the upper left corner of the Preview Pane, and also in integrated applications' document selection dialogs, a thumbnail image of the selected document displays. If no thumbnail image exists for the selected document, then a default image displays in its place. Thumbnail images are generated by your administrator.