No height requirement on junction boxes. They are only required to be accessible. The definition of accessible in the code does not include words like “easy” or “fun”. There are a couple of apparent violations in that picture, such as the 2" connector is not okayed for 12 romexes, the cable do not appear to be fastened within 12" of the box, and the box does not appear to be bonded with the largest equipment grounding conductor that enters the box. The equipment grounding conductors only appear to be twisted, with no mechanical splicing means.