Nose length in your pic @DogHairHereAndThere is much better, but please please tell me your dog had been running VERY hard immediately before this pic was taken, as his face tells me he is struggling for breathe there.
The tongue out pant with a tongue under tension (see stuck straight out, see the muscle under the tongue and the curled tip) is a sign of that, as is are the wrinkles at the back of the cheeks, where his mouth is open and commisure drawn right back.
For a dog that has just exerted itself really hard, thats normal for a short while but if it's happening whilst your dog is walking at a normal human pace, or just trotting about in a relaxed fashion (or worse still lying around doing nothing) its a significant problem.
Your dog also has pinched nares and a fairly short neck and those features will also affect breathing.
I am sure you know all this, but the reality is many people do not, and many people would see your photo and think thats a happy dog, because lips back, mouth open, tongue out = happy dog, right?... and they cannot tell the difference between a relaxed open mouthed smile, and a dog desperately gasping for breath!
There's some good photos that show the difference between 'stressed' and 'relaxed' here eileenanddogs.com/blog/2014/05/30/dog-commissures-smile-happy-stressed/ (Although this is in relation to general stress rather than physical stress, its still useful.. being unable to breathe easily IS stressful, I know from personal experience!)