In Picasa, in the Properties List, there is a property labeled "Unique Id".
In the Exif spec, there is a field called
However, I have tried several Exif libraries/command line tools (e.g.
exiftool), and none of them show ImageUniqueId.
So — is the Picasa "Unique ID" something that is stored in the image metadata, or is it something that Picasa computes on the fly?
If the latter, what is the algorithm that Picasa uses?