Getting arbitrary aspect ratio images on Plane without distorting aspect ratio and just scaling and cropping automatically

Hi.
I am trying to mimic something that VizRT does to put arbitrary images in a screen without distorting aspect ratio, merely scale and offset.

With a known aspect ratio image I can just set appropriate UV + and * with text coord but obviously this wont work with an image that has different AR unless I manually tweak the U and V multipliers, which would also mean needing to know texture dimensions.

Is there a way of getting the dimensions of a texture such that I can use them as U and V multipliers?

The context of this is I want to allow Studio directors to be able to test arbitrary images in a video wall with in TV show previz environment using UE in such a way as the images are not distorted.

Thanks and sorry for the rambling nature of the question!