Honestly I would suggest IGNORING all photos in ads, except (only in some very specific circumstances) they show things that should warn a novice rider away from the horse. That is, I would not go drawing optimistic expectations from photos, nor mildly-pessimistic ones either.
As I think wc has said, the conformation requirements for "I want a basic sensible horse to get me back riding again" are exceedingly loose, and you can even waffle a little on soundness if you are ok with absorbing the risk of things taking a turn for the worse and being unable to use or resell the horse easily. Although for a heavier novice rider I would not bother driving far to look at horses with structurally- or muscularly-weak toplines.
What you really need is excellent temperament and good fundamental training and the right "click" with your own personality, none of which can be assessed from a photo. Do not be impressed with photos of the horse being ridden well, or having someone lie down atop it, or anything like that -- says nothing about what the horse will be like for YOU.
I *would* suggest a novice not bother (or anyhow not drive very far at all) to visit horses whose ad pictures show them being ridden in highly dysfunctional ways... extremely hollow, pulling against bit, prancing behind bit, anything like that. While it is *possible* it's just rider error and the horse would be fine for you, it is not very *likely* in my experience. Also if you care significantly about long-term soundness there is a limit to how far it's probably worth driving to look at horses who you can see signs, in their photos, highly suggestive of lameness (consistant pointing of one foot in multiple pics, muscling abnormalities that usually reflect lameness, super messed-up hooves, hocks straightened due to dropped hind pasterns, etc)
Really, though, overall, ad pics don't mean much more (for a novice wanting a general userfriendly horse) than "new, improved!" does on a box of cereal, or the color of a piece of candy
JMHO,
Pat