Very impressive the detail in the scales is well appreciated. Your transition to the dragon's belly is subtle from the scales but I understand how much time that sort of thing takes. I'm most impressed with the dragon's eye and how you've effectively built the scales. The volume is very believable. What could help aside from atmospheric perspective is blur for more depth. I understand if that's difficult because with my work, doing detail and then blurring it seems so counterproductive but sometimes it really boosts depth.
Overall great stuff.