Type about:cache in the URL bar and hit Enter.
Memory cache device - ===List Cache entries===

thanks that will come in helpful, but what I mean is the images files themselves. this seems to have only the url. what I mean is if I go to "page info" on a site and I can see the image, but I'm unable to save it because it is no long on the site.......does Firefox have just the image in somekind of cache?

thanks again

Images are in the cache too, but they aren't listed separate from other content in the cache. Use the Find bar {Ctrl + F} and type in jpg or png and use the Next button to "scroll" thru those image type URL's.

You could try the Cache Viewer extension.
https://addons.mozilla.org/en-US/firefox/addon/2489/

I did that but some of the images I'm talking about are no longer on the server. what a shame that the Cache Viewer is not available for the 3.6 version of Firefox.

thanks again

Works with Firefox 3.0 - 3.6.*

Firefox uses two caches, a disk cache and a memory cache.
You can find the location of the two caches on the about:cache page (open that page via the location bar like a website).
Only large image and media files are stored as individual files on disk.
Other files are stored in a few large container files (_CACHE_XXX_) in the cache folder and not as separate files on disk.
The individual files on disk have random names without a file extension for security reasons.

You can look at this extension for easier access to files in the cache.

• Cache Viewer: https://addons.mozilla.org/firefox/addon/2489