I mean that the photo is perfect
I dont think it makes a sad impression, but you could ask many persons that would give you different answers about it.
It's a picture, you have to think about it! it may be a sad one, with tears in the next moment, but also one with an happy occasion
There is something in this picture that makes it different, it's very amazing!
This is a very odd way to put it.
I would say something such as if I were single, I'd ask you to marry me but "beautiful as $#%!"?