This is a mass search for bugs which are in the Firefox General component, are UNCO, have not been changed for 500 days and have an unspecified version. Reporter, can you please update to Firefox 3.6.10 or later, create a fresh profile, http://support.mozilla.com/en-US/kb/managing+profiles, and test again. If you still see the issue, please update this bug. If the issue is gone, please set the status to RESOLVED > WORKSFORME.
I have juste performed the test as I had described the first time around, using a different image for the source as this source is no longer available. I confirm this problem is still present, there is no way of having the image be refreshed when reloaded into a page, even if it has expired. :(
I am running into a similar problem with my development. I am modifying an img tag's src attribute and if I end up putting the src attribute to a previous URL, that the browser had made a request, for it will not request the image again. An example of the code is here: http://jsbin.com/ulobo5/5 The first image is cached so it shouldn't re-request it. The second image which is a no-store, no-cache is not being requested when it is set a second time. If the browser was respecting the caching header the captcha should be a different image each time the captcha comes up.
Bug 183470 seems to be addressing a similar issue but it has deviated a bit.
Firefox 3.6 is now EOL, please try latest version of Firefox and feel free to open if it reproducible on latest build * http://getfirefox.com for support * https://support.mozilla.org/questions/new