Digital cameras can occasionally do strange things in terms of coloration depending on lighting conditions and/or the way the user had the camera settings configured. The fact the the pictures were of poor quality is more a reflection on the listing agent who when looking at them decided they were good enough to use rather than having the shot again or better yet having used a professional photographer to begin with. Doe's it really matter what color the house is, when the day is done it's only paint and paint is the least significant issue to consider when purchasing a home.
If a seller has had a suggestion from their agent that if they can afford to paint and it needed to be painted, they are going to go with a current favorite color palate of buyers. Coffee Brown beats Sky Blue hands down every day in curb appeal. You should be thrilled the sellers painted.
Unfortunately, it's not uncommon to see, shall we say, overly flattering photos posted of listings. All I can say is that I try very hard to post accurate professionally shot photos when marketing my listings, but not all agents do that. It's always important to see the actual properties before judging them. I should say too that often photos are so carelessly shot that they make a property look worse than it actually is. I hope that helps.