Try looking up US Army ordnance unit or depot in your image searches. The stuff was documented, it's just all in the terminology.
Years ago I had a fantastic photo book, "The War in Europe". It was a compilation of US Army Signal Corps photos documenting the Army's role in the war in the ETO, from the first arrivals to VE Day. It covered such mundane things as shoe repair, and all the other unsung support personnel, as well as the leaders and the grunts, tankers, etc. It is published by the Centerfor Military History as part of the official Army History of WWII. Unfortunately my copy was water damaged by a broken pipe and subsequently disposed of. But it has the sort of photos your looking for, along with all sorts of combat photos. There are similar volumes for the MTO and PTO.
F is for FIRE, That burns down the whole town!
U is for URANIUM... BOMBS!
N is for NO SURVIVORS...