As others have stated; it is the listing agent who takes the photos on their listings or they hire a professional photographer. Trulia has nothing to do with how listing photos can be poor quality or lacking in number as they are a home search site which listings feed into. The listing agent has all the power on which photos are shown and how many.
Prudential Connecticut Realty
I have a lot of pet peeves about photos. (1) I don't like to see the toilet seat lid up. We know what it's used for, so please closed it before taking the photo (2) Can you see yourself in the mirror? Then so can we. Don't use it (3) Children, pets, or other people should not be in the photos. (4) TV? Turn it off. We don't care who Dr. Phil has on his show. (5) Outdated photos. Retake them after the Christmas decorations are down. (6) Your purse? Seriously could you just move it out of the shot? (7) Sideways photos. Do you even look at what you post on the MLS and internet?
Those are just a few. I won't even get started on the comments, like "This house will sell itself" or " It won't last." When after 30 days it's still on.
Keep note of those agents and decide whether or not it's an agent you would want to represent you in your purchase or sale.
Have an amazing day!