A few days ago I blogged about how neat it was that when I browsed the BBC News via a GPRS/HSDPA connection, the JPEGs were all magically degraded to cause them to load quicker.
Had I stopped to think about this for a while I would have realised that it was not specific to that one site, nor could it have feasibly been implemented by the Beeb. The functionality is inserted by Vodafone, my mobile carrier, and affects all JPEGs (it just so happened that BBC News is one of the sites I often visit when out and about, and it was obvious that the usually high-quality photographs were being degraded).
Investigating a bit more, what's really neat is that the JPEGs have had their ALT tags modified, to point out that hitting Shift-R when hovering over an image will the original version to be asynchronously loaded:
After hitting Shift-R, Harriet and Gordon are considerably less "furry":
I really should have just Googled this a week ago!