New parameters for {gallery} macro

It would be nice if we had the following parameters (apologies if these have been added in a Confluence 2.x build):

• extensions = comma separated list of image extensions to include (default = all). Eg. I might just want to show .png's or .gif's
• size = override thumbnail size - I might want to show herds of images on a page so use a thumb size of 100px wheras another page might only have a small number of files so I might want them bigger, say 300px

(Yes, I know the thum size can be set in admin console, but it would be nice to be able to override it if necessary just for one page - or maybe even set a default on a space by space basis?)

Also, what image formats are supported?