In this day and age, I personally think it's rather ill conceived of anyone to not utilize every advantage they can come up with in order to try to sell their animals. With the number of options available for people to take photos and provide them in ads on the internet, seriously, it's hard to defend any excuse for not doing so. But make it a rule? Nope, that's just not going to happen. I try to give people a lot of freedom here, even if it means allowing them to choose unwisely sometimes. Choosing to NOT provide photos to catch the eyes and interest of someone, in my opinion, is just plain foolish. Why make a rule to try to smarten them up? The marketplace will tend to weed them out sooner or later, I suppose.
But you want to know something else that has always baffled me? Why in the world would someone go through all the effort to list something for sale and then neglect to provide one of the most important bits of information to a reader? I'm talking about price, of course. I don't know how many times I have asked for information over the years on something or another from a seller (in all types of lines of interest) and then gotten expensive copy sent to me with everything BUT the price enclosed. Well, I just throw it in the trash, of course. And put the seller on the list of companies that are just wasting my time. If they feel the need to have a fast talking salesman trying to set a hook in me, then that is a near certainty that they want more than even they think they should be selling it for.
To paraphrase a popular saying, "If I have to ask, then it's probably worth more to you than to me, anyway."
And I NEVER play the game of "Well, how much are you willing to pay for it?" If YOU are offering it for sale, state the blasted price you want and be done with it.