There is a difference in the detail from the photos vs screencaps
yes, but its not because it happens to be a screencap vs a pic.
one, the lighting is totally different.
two, the pics are not taken at the exact same time or state of contraction.
ND, the only way to prove what you are saying is to take a screencap of the exact instant from a clip and compare to the exact same pic taken at the exact same angle with the exact same lighting...
thats the only way to know.
you can't take a screencap that is totally different and from a totally differernt angle/lighting as a pic and proclaim there to be a difference in detail.'
it doesn't work that way..
however, if you compare screencap to video, you will see the EXACT same level of detail:
look: