EDIT
Edit: This opens the currently selected picture in the editor specified in preferences.
Copy Picture: This copies the selected picture to the clipboard in Bitmap form.
Copy Path: This copies the filename and path of the selected picture to the clipboard in standard text format.
Paste Picture: This adds any Bitmap picture on the clipboard to the album and saves it to disk.
Paste Path: If a filename and path are contained on the clipboard, this will add the picture they refer to, to the album.
Delete: This removes the selected picture from the album.
Delete File: This removes the selected picture from the album and deletes the picture file from the disk. (Confirmation is asked for before this occurs.)