Yes, #3 in particular looks like a pressure ulcer that's been surgically debrided. Adding, of course, that pressure ulcers are a terrific way to introduce OM.
Long story short, don't be diabetic :/
Most of these are actually depictions of gangrenous necrosis. Could be caused by osteomyelitis, but only with bacterial invasion into contiguous tissue.
Fortunately, this sort of tissue death is not enormously common in OM alone, more common if there's some co-morbidity such as peripheral vascular disease or diabetic neuropathy.
I just realised that the odds of anyone being interested in my rant is low. Eh, have it anyway :P
For him it started with his foot bones collapsing from diabetes injury (Charcot foot). He was misdiagnosed with pinched nerve and foot drop and continued to walk on his broken foot until he crushed it further and further. Then bones in the wrong places started poking at his skin, creating holes letting bacteria in infecting the bone. The infection then spread both from the outside and inside of the foot. His foot is also having parts with necrosis so I don't think the pics are all incorrect compared to his deal. I assume they will just cut it off eventually, after spending a million dollars on other treatment that is wasted on him, since he doesn't take care of himself.
I'm always interested in medical shit.