Upfront Gallery, how to increase thumbnail width...

Hey WPMU,

Hope all's well.

I'm just looking at your Upfront image gallery.

One thing I've noticed is that I can't seem to get the thumbnail images bigger than 250 px, so they don't fully stretch the width of the container, so they look a bit small!

My gallery settings screenshot attached.

The full size images are 800 x 800 - do they need to be bigger?

Can they be made to stretch the container?

If not I guess I could use JetPack's gallery which is nice...

Thanks for looking.
Kevin