Did I hear out there anywhere the term "six throw rule"? Also all I read is that this is a sub panel. Yes, sub panels are to have their neutral and ground separate however do we know if this sub is even in the same building?
Back to the six thro rule. So far I count what maybe eight breaker positions. I don't see a main breaker in that panel. If the main is very near by and maybe even in the same building an inspector may let you get by with it but that panel should have a main breaker in it and if it is in a separate building the grounding should be performed a bit different (well in addition) to what is normally done.
How many breakers is that panel able to handle by its rating? Is the sub in a different building (detached) from the main panel that is feeding it or very close by let's say within an eye shot?