How to not cache certain images

[Capo64]

I have no idea how caching works, and I'm trying not to cache an image that dynamically changes, how do i do this? (It's actually an image that displays whether or not my AIM screenname is online and it uses code like this):

<img src="http://big.oscar.aol.com/MyScreenName?on_url=online.bmp&off_url=offline.bmp">

[john8]

If my understanding is right, this BMP is managed by AOL, so you can't set cache expire time for them. But this matter may be already handled by AOL, it'll not be cached.

If you are using apache, you can set the cache expire time using .htacess.

[Capo64]

offline and online.bmp are hosted by me, they had my full web address in it, but i took it out. so how would I do it with apache? I tried looking and whatever i do i get the internal server error..

[john8]

try this in .htaccess

<IfModule mod_headers.c>
<FilesMatch "line\.bmp$">
Header unset Cache-Control
</FilesMatch>
</IfModule>

[Capo64]

Ooh that worked I think, thank you very much