JpegRDF

The JpegRDF documentation claims that the subject for
statements made about the image will be set to '', but this
is not the actual JpegRDF behavior. Instead, the stored
RDF (or at least, the RDF stored using `JpegRDF -s
image.jpg`) sets the subject to file:/full/path/to/image.jpg.
Clearly, this is not portable; either JpegRDF ought to
operate as described in its documentation, or it ought to
allow the user to input the URI (or perhaps a catalog
mapping from filenames -> URI) from which the application
can take the subject URI.