The very act of displaying artwork is to invite criticism. Whether that criticism is positive or negative, you must be willing to accept any and all opinions on your work whether you agree with them or not. If a person can't take criticism then he should consider whether he really wants to display his art.
Although a photograph is a relatively permanent representation of the artist's internal vision, art is not static. The photographer grows and changes with each photograph he creates. If he is to keep on growing and improve himself he must accept some negative criticism or else he will not be motivated to grow and improve himself. If all he ever hears is, "That's wonderful!" he will keep repeating he same old things over and over. He will not grow. His art will become stagnant.
That having been said, the photographer has to decide whether to accept criticism or to blow it off. It's hard to say how to decide that. Do you respect the person giving the criticism? Or, do you, at least, respect the person's artistic credentials or ability? Is the person's criticism respectful of your work or do they just cut you down in order to make themselves feel superior? Is the person's criticism of your work balanced?
A balanced critique is probably the number one thing that makes me decide whether to accept an opinion or not. If somebody just cuts me down and doesn't even give one positive word I am likely to think "F*** you!" and walk away.
Personally, I'd rather hear 100 negative comments on my photos than to have 1 glowing, positive comment.
I think the most important thing for a photographer or any artist to have is a thick skin.
You are bound to get criticized by idiots and crackpots and people who are just out to satisfy their own egos by trying to take you down. You are also just as likely to get glowing reviews by shallow people who will not understand your work who will say anything for attention. You've got to learn to filter out those kinds of people from both ends of the spectrum. Listen to the comments that come from the middle. Basically just take the rest with a grain of salt.
I like all four of your photos. I like dogs. I grew up around dogs. My father bred and trained hunting dogs when I was a kid.
I think you might be right about the quality of the scans. Since I can not see the originals it's hard to judge. I can only judge what I see. I see virtually no problems with focus or composition, however.
The color photo of the Shepherd is good. I don't see anything in that picture, exposure-wise or color-wise that can not be tweaked. Maybe, it's a hair bit yellow. It's an outdoor shot of a dog who was probably moving around a lot. You're probably going to have to take what you can get. Right?
The narrow depth of field takes you right to the dog's eyes. I've always thought Shepherds have expressive eyes.
It took me a minute to figure out what he was chewing on. Maybe you could change the angle of the shot so the viewer can see what the dog is doing.
The second one is a police dog in training. Right?
It makes me think, "If it wasn't for that handler with the collar on that dog, he'd tear my leg off!"
It looks like the light might have been flat but the contrast of the picture was pumped up to compensate.
But, you know what? That kind of works. Since the subject is so compelling the contrast sort of adds to it.
It kind of reminds me of a chase scene in a movie.
Subject and composition-wise... No problems. You decide on the contrast. Make it the way you think is best.
The third and the fourth one are nice. They remind me of the times my Dad trained his hunting dogs. I really like the one of the dog drinking.
The contrast on the fourth one (drinking dog) is a little hard. I can see that you were in a hard-contrast light so you were working against Mother Nature on that one. Again, when you are working with dogs, they can move and run at any second so you're probably going to have to take what you can get.
I would like to see some more texture in the dog's fur, especially on the fourth one But it is a black and white dog. That is a REALLY hard thing to get perfect.
(I once tried to photograph a black Labrador retriever standing on a snow bank on a bright, sunny winter day. It just didn't work.)
For subject and composition, I'd give an 8 or 9.
For exposure and technical, I'd give a 7 or 8 but I think I would give an extra point because you were working in hard light with a somewhat difficult subject.
With that in mind, I'd give a solid 8, overall.
But... Know what? The last time I checked, we still lived in a free country!
They are your photographs. Make them any way you damn-well please!