WordPress.org how to force expire Cached Banner-772×250 from my Plugin page

This was discussed on the WP Hackers mailing list.

On Tue, Jul 31, 2012 at 7:15 PM, Dion Hulse (dd32) wrote:

s-plugins.wordpress.org is a Externally hosted CDN – Edgecast to be specific.

Right now, the only way is to wait for it to update, the Edgecast CDN
has a long cache expiry time, so WordPress.org needs to be updated to
add a Cache busting version/revision parameter by the look of it.

The cache-busting parameter has been implemented now. It will take
effect on the next plugin update.

So touch the plugin’s readme.txt file or perform some other update of
your choice, and the cache will get busted for your banner image. It
will then get busted again when you change something in the assets
directory going forward.