file_id
Description:
The ID of the file.
This is a substring of the ID returned by get_id for PicasaWebFiles; for example, if get_id returned "http://picasaweb.google.com/data/entry/user/libgdata.picasaweb/albumid/5328889949261497249/photoid/5328890138794566386" for a particular PicasaWebFile, the file_id property would be "5328890138794566386".
For more information, see the gphoto specification .