I love the emotion portrayed in both of the wolves faces. Even by simply looking at their eyes, you can read exactly what they are thinking. If I didn't know any better, I would have thought that this image was faked. Well done!
The super snarl wolf is the omega, He's got his ears back and tail tucked showing classic signs of fear, he's also not looking the Alpha female in the eyes, the bared teeth is like saying "Alright already! leave me alone!"
The non-growling wolf looks like he's thinking "What did I do wrong?". His little eyebrows seemed raised and everything~ Great action shot, by the way. The focus looks perfect and wow! Those teeth! I'd hate to be on the wrong side of those.
The left is the alpha female and the right is the omega male. He's all defensive and just snapped at her fur in this frame. The alpha female seems surprised nevertheless, and is a bit impressed, laying her ears back a little. However, she then started taking the initiative again a moment later.