Just a quick note & haven't read replies, so sorry if I repeat... From what can be told of those pics, nice, healthy, strong looking frogs!
Firstly, are you absolutely sure the horse was trimmed but 2 hrs previously?? Perhaps the fronts were 'rolled' a bit(except maybe the outside left), but apart from that, esp the backs, there is no real evidence of a recent trim IMO. Of course, with only those pics to go on, could be wrong, but if they were, esp backs, it wasn't a good one. Hope it's not some 'professional's' eg.... Perhaps you trimmed them yourself(before going on a long abrasive trim that took care of evidence...), but I'm afraid I'd advise not doing it again unless under guidance of a *good* trimmer/farrier. While fronts aren't terrible(tho there are issues still), backs need much more/different.
Be helpful to see the sole on an angle, to better gauge depth / wall height. Quarters(both ground surface & flares) & bars appear undealt with particularly. What's the horse's history? Be interested to see before shots. What's his diet/nutrition like? Environment? Has it been recently long-term wet & just dried out or such? IME those kind of cracks are most often a sign of diet/nutrition probs, &/or of using some kind of topical that has robbed the wall of it's outer protective layer, so allowed it to dry out excessively &/or the horse has been standing long term in mud without respite - altho I wouldn't think the last in this instance. If you've been using topical goop of any kind, I'd quit that, for starters.