“…the replacement of ‘visual art’ by texts was being celebrated as the driving out of allusion and shadow by transparency – a direct channel thereby being opened to the ‘meanings’ and ‘intentions’ of the artist” – ‘Almost Too dark To See’, Charles Harrison ibid.
‘JPEG is designed for compressing either full-color or gray-scale images
of natural, real-world scenes. It works well on photographs, naturalistic
artwork, and similar material; not so well on lettering, simple cartoons,
or line drawings. JPEG handles only still images, but there is a related
standard called MPEG for motion pictures.
JPEG is “lossy,” meaning that the decompressed image isn’t quite the same as
the one you started with. (There are lossless image compression algorithms,
but JPEG achieves much greater compression than is possible with lossless
methods.) JPEG is designed to exploit known limitations of the human eye,
notably the fact that small color changes are perceived less accurately than
small changes in brightness. Thus, JPEG is intended for compressing images
that will be looked at by humans. If you plan to machine-analyze your
images, the small errors introduced by JPEG may be a problem for you, even
if they are invisible to the eye.’ – http://www.faqs.org/faqs/jpeg-faq/part1/