Who says they are taking photo's in the visable light spectrum.
If they take photo's in the IR spectrum they can spot leaks and other such stuff. They were accused a few years ago of leaking into the forth. IR photo's can spot gas leaks. Early morning is when the earth is cool giving a good contrasting background.
And I have seen the goundflare dump at another plant and I don't think 3000ft would be enough, yes the flames go up 300-500ft but the thermal will go up and up
And in that first thermal the steam catalyst system won't be up to temp so there will be literally tons of CO in the plume and very possibly enough CO2 to stop the engine. And as its a refinary there will also be Sulphur compounds in it which are rather fatal in very small quanities.