ExifTool is a flexible and comprehensive tool to keep metadata, e.g., keywords and identifiers with the files and images they describe.

It handles a wide variety of metadata, including:

and a plethora of file formats.

This is a tool well worth space in your quiver.

Harvey, Phil. 2003. “ExifTool by Phil Harvey.” Software Tool. ExifTool. November 29. http://bit.ly/1crXoFE.