Hi. Didn't see this post for a while...
Hi Jim, just coming back to you on this, how 'safe' do you think it would
be -- i.e. can we make sure it works for all users, aside from those who
can't be identified and go to fallback mode?
I can't think of any reason why a browser would care if the http response
isn't sent straight away after the request. Afterall, most dynamic HTML
pages aren't made in zero seconds.
The only certain answer is you'd have to try it out, but there is no reason
in principle it wouldn't be safe.
Also, can it be applied only to certain pages or would it have to affect
the
entire site?
Ideally we'd like it just on the streetscape pages.
Sure, it can work however it is coded to work. You could check the REFERER
header to see what page the user is requesting the image from. Browsers
aren't required to send this header, but pretty much all do and you could
just fallback when it isn't there. Alternatively, you could put a param in
the image URL indicating which page the image being asked for is on. There
are plenty of ways it could be done.