Until I found a very informative forum contribution from Aso
Type about:config in FF and search for 'cache'.
Check
browser.cache.disk.enable
browser.cache.memory.enable and
network.http.use-cache
are set to true.
Also try cranking up the size of browser.cache.disk.capacity (50000).
Lastly, make sure browser.cache.check_doc_frequency is integer 3.
Another thing I should mention - when you say you 'reload' the page, are you hitting refresh? Because this effectively reloads the page (and all it's objects) from the server, so you will not experience the effect of cache. Only when browsing a site will cache make a difference.
