Opinions please. Please look at the pictures that show a sub panel mounted directly adjacent to the main panel. Notice how there is only one neutral (and one ground out of picture) attached inside the sub panel. The remaining neutrals and grounds are attached inside the adjacent main panel. My instincts say it is incorrect but I would like other opinions please.
Then is seems as though that the one 120 volt circuit is on the 15 amp breaker and then there are four more circuits installed on the four 20 amp breakers as multiwire circuits. Then yes the neutrals would need to be in the same panel as the breakers.
On a side note the PVC will also require an equipment grounding conductor
As long as the neutral and ground where brought over from the main panel (which it looks to be the case as there are 3 wires feeding the subpanel) AND the connecting conduit is not more than 18" long, this is code compliant in NH.