I deleted the Heston Phoenix photo at the same time as I uploaded this one, so I've no idea what caused the glitch - 'tweren't me, honest!
No - it wasn't. Some ISP's cache data retrieved by their users so that the next time you load the page it is from the local server and therefore a lot faster. It normally works quite well unless, as in this case, a picture is changed (same filename, different picture). Some users will still get the cached picture from the local server unless they force a full refresh as Treaders suggested.
Now let's see what 185Skywagon can throw at us..