Timestamps on links

[bambua]

I'm looking at using some avatar and css links in a wordpress theme and just had a question if anyone might have an answer.

The links for both at the tailend of them have a ?timestamp when they were last modified. How is that timestamp used by the system? It doesn't seem to on the avatar, but on the css.php files does that pick a particular version of the css files?

Thanks all

 

[Paul B]

The query string is used to invalidate any cache so people see a new avatar immediately.