Ilena52, my 2 cents on your images…
I like the sense of the images, but you really like dark images, don’t you? 
Honestly, in my initial views of the two images, especially the second, I couldn’t figure out what they were. If you bring the second into Photoshop and check the levels, you’ll see that 90% of the image is almost totally black. Now I know you want it dark to imply suspense and imminent danger, but areas of total or near black don’t really provide any sensation or interest. And the character hiding in the darkness is pretty much indistinguishable, and without some clear highlighting you can’t see the evil in his eyes, or even what he is. Maybe a single shaft of light piercing the trees and only partially lighting his face, to show evil glowing eyes and a toothy snarl, dripping saliva, etc.
The first image is a similar, but not as much. It is mostly black or white, with very little midrange. I honestly couldn’t tell from the dragon’s wings what it was, and it looked more like some sort of spear or weapon in her hand. I assume you want the second image to have a sense of serenity, but with such a high contrast image with only black and white, you’re losing the opportunity to have softness and beauty, such as soft light streaming thru the green leaves casting a serene soft light on everything. I think that, by not really showing much more than the dragon’s wings, you’ve also lost the opportunity to depict a very interesting character, a pet dragon that would make most viewers think “Ahhh, how sweet…” 
Given the choice between totally black and/or totally white, versus a fuller range of color and shading, I think choosing a fuller range can give you the opportunity to depict a lot more emotion and dynamics and story. And that certainly doesn’t mean you need to make all your dark areas light, just give them a slightly broader dynamic range to provide some interest. The old masters of black and white film noir were experts at that. But with CG we have even more control and can paint an even broader range of emotion.