I'm building a site for a photographer who uploads pictures that are normally large for todays digital cameras. Images are quite memory intensive, especially the image operations like creating thumbnails.

So I wanted to raise the memory limit in the admin above 256MB - how can this be done? I allowed CGI and PHP to use up to 1 Gigabyte but wordpress always decreases the memory to 256MB. Any idea how to fix that on a client side that needs to be able to auto-update?

UPDATE: From Wordpress 3.2 ongoing the maximum memory limit in Wordpress will be configure-able again.