If I'm not mistaken there is a tree under the wing on the left side of the pic. I'm not sure, but it looks like one and if so it shows a very good scale.
But you have to remember that everything you can "place" in the toolset is scaleable. You don't want your dragon to be tree size, then make it bigger or smaller to suit your needs. The PC, placeables, items, everything you can put into the tileset is scaleable but may look a bit wonky if they get too big for their animations.
Just in case you guys weren't following it as closely as those of us over at the Biobsidian forum