The bad thing about pictures is so many people don't know how to take decent pictures or they refuse to take fuzzy pictures. Or they avoid the angle that shows the problems.
That one is simple--if you don't get the photos that you want to see...photos that show you what you need to see in order to make a decision, then pass on the horse. For whatever reason that some seller does not send decent photos that allow you to see conformation, if you ("you" speaking generally, not anyone specific) decide to purchase the horse based on photos that don't allow you to judge the conformation, that is your choice, not the fault of the seller. It's impossible to know whether the seller is deliberately hiding some fault by not sending photos which show that fault, or if they simply don't know how to take a decent photo. Some people never take anything but funny angled shots--I think they think they're being artistic by taking front angled shots--some buy horses from photos like that all the time and so think that's the kind of photos people want to see. Some cannot judge conformation anyway, so why look at (or take) a full side view that shows conformation....they want photos that show off the head & neck to its best advantage. (Seriously!!) Some people simply can't take a decent photo to save their lives!
I know people who will rave about some horse--they will tell you it is the most awesome horse they've ever seen. When you ask what is so awesome about the horse....they cannot really tell you. They've fallen in love with their first impression of the horse, and have never bothered to really look at the horse and figure out what its conformational strengths and weaknesses are.
I don't dispute that there are dishonest sellers out there. But I maintain that there are a lot of completely clued out sellers out there too. They try to mimic sales pitches that they themselves have been given by other sellers--they don't honestly know what they've got in terms of quality in their horse, they're just trying to make it sound really good (which they believe it to be) because that's how it was presented to them when they bought it....
As far as asking about testicles or height--that is harder, because you do depend on the seller's word for those things. You can get a photo of the horse being measured--that lets you see how the horse was standing for measuring. Honestly, there are people who believe it's perfectly acceptable to stand the horse anyway it takes to get that horse to measure a certain size. They aren't lying when they say the horse is 34"--they just believe that it's proper to stand the horse stretched & push down on his back to get him to sag to make that under 34" measurement. Testicles....making sure there are 2 could be done by way of a pre-purchase exam--something that is done a lot in big horses, not so much in Minis. A PPE is done by a vet of your choice, paid for by you, the buyer, so the word you get on the horse isn't based on any loyalty the vet may have toward his regular client. It is also good to include testicles and height as guarantees in the sales contract--along with details of what will happen if the horse arrives and is over the guaranteed height or if he doesn't have both testicles down...contracts should be very specific when certain things are of high importance. If seller balks at such guarantees, then you have a warning flag & can choose to walk away from the deal.
Of course you can still have a detailed contract & a seller may still try to back out of terms of the deal if the buyer tries to collect on it--then you know you've got a crooked seller (unless buyer is being unreasonable, complaining about height when in truth the real problem is buyer doesn't like something else about the horse...something not guaranteed in the contract, so they are trying to use something that is in the contract to get their money back--and yes, I've known of that to happen too!!) I'm not into selling horses (have bought many though!) & after knowing some of the situations that friends have found themselves in with buyers I have to say that it's just as well that I wasn't trying to do much selling. I can tell you that I don't have the patience to deal with some of the people those friends have encountered!
I have never understood why so many people continue to buy horses on application, or horses that are registered but their papers haven't been kept up to date, so are 3 owners behind. And I sure don't understand breeders who wait to register their foals, or who buy mares & breed them without bothering to transfer the papers first. If you're breeding a mare, why don't you want your name showing as breeder on the papers of the resulting foal? If you buy a horse to show, why do you want to show that horse under someone else's name? If you're in Canada, why do you want to show that AMHR or ASPC horse under the name of the non-Canadian seller, so that you miss out on any Canadian All Star awards that they horse may have been eligible for if you had him in your name???