Background Image Editor

This must be a simple thing I'm not grasping, but can anyone tell me what the circle/bullseye does when in the background image selector?  You can move it around but I don't see that it changes anything.  See screenshot.

Hi @GeoDataWorks

It's the Focal Point:

https://support.squarespace.com/hc/en-us/articles/205826028#toc-images-with-focal-points

Thank you.  It wasn't doing anything for the first few images I was moving it for b/c (I think) they were not large enough to move the image w/in the defined dimensions.