On Tue, 24 Nov 2009 00:23:58 +0100, Henrik Nordstrom <henrik@xxxxxxxxxxxxxxxxxxx> wrote: > mån 2009-11-23 klockan 15:34 +0100 skrev Sébastien WENSKE: >> Sorry I've make a mistake, the url to get the original picture is >> http://gallery.wenske.fr/wallpapers/holland_dream_2560x1600.jpg.html?z&p=full-image >> >> This will force the download of the picture. > > That's a very very cache-unfriendly object.. > > Some key elements from the response header: > > Expires: Thu, 19 Nov 1981 08:52:00 GMT > > Cache-Control: no-store, no-cache, must-revalidate, post-check=0, > pre-check=0 > > Pragma: no-cache > > Last-Modified: Mon, 23 Nov 2009 23:14:13 GMT > > Vary: Accept-Encoding > > > > And my comments: > > Expires is set in the past, which forces caches to revalidate the object > on each request. > > Cache-Control no-store is a very aggressive nocache directive. Forbids > everyone involved from storing the response on any form of persistent > storage. I.e. not even browsers are allowed to cache the object in their > disk cache, and they must also remove it as soon as possible from the > memory cache. Really only intended for very sensitive responses where it > would be a major disaster if an unauthorized third party got hold of the > response by stealing the computer and inspecting the cached files and > similar scenarios. > > Cache-Control no-cache & must-revalidate, also quite unfriendly and says > that the response MUST be validated with the origin before reuse. ... added to all that... According to redbot.org: "An If-Modified-Since conditional request returned the full content unchanged." Amos
