Gets internal information from the image.
Internal information is format specific so you need to use
different selectors with different formats.
The JPEG 2000 format implements a "Structure" info which
provides the tag structure of the raw data together with types,
offsets and lengths. This can be used to modify or insert tags for
The TIFF format implements a "TiffTag:" info which allows you to
get the values of TIFF tags either by name or number. Simply append
the item you are interested in. For example you might use
"TiffTag:InkNames" to get the ink or "TiffTag:271" to retrieve the