Yes, a pic of your horse's crack(sounds rude!) would be good, as well as a range of angles, if your horse's crack does indeed look like the one you pictured. As someone also mentioned, she may have a 'hairline' surface crack or 'dent' from an old injury, which may be a permanent thing & nothing to worry about.
But the crack pictured is not of the above nature. It is not a surface crack, altho it may still be in the top section. It is by no means a huge problem, but it is a symptom of imbalanced hooves(eg. Quarters left too long & flaring) Cracks such as this generally come about due to overlong walls(too much pressure on them) &/or badly balanced feet, and can remain even despite good farriery, due to infection getting in.
I would therefore be soaking the hoof twice daily for a few days at least, in something to kill the infection, and ensuring the hoof is *kept* well & frequently trimmed, to keep leverage forces acting against the walls. I would also continue to soak daily in ACV or some such to deter reinfection, until the crack has grown out.