In 1.5 (assuming there are no objections), image width, height and bit depth will be available in the image table of the database. This is mainly for scalability. It allows replication and read load distribution of this commonly requested data to be handled by the database, where we already have tools for such things. A simple future extension would be to bundle metadata queries for all images to be displayed on a page into a single query. This is only a few lines away now, but was not possible with the original NFS-based system.
Thumbnails are still not handled in a way suitable for our scalability goals, this will be my next task.
The code is in CVS.
-- Tim Starling