Cache buttons etc images

[Gearloose]

Is there a way of caching only some groups of images and not all of them?

E.g. I want the browser to use its cache for buttons, IM images, smilies (maybe and some other groups of images that don't change in every visit) but I don't want it to use the cache for status icons and the rest of the images that may have changed from the previous time that a user visited the forum.

Sinse some group of images don't change (while other change in every visit of a member in the forum) is there a way to do it?


I asked this in vb.com and Steve said that he is not sure this is even possible but if so it requires modifying the code.

Do you think is it possible to achieve something like this?
Is there something like this available, or could someone point me in the right direction so I can make a hack for this?