The settling of something unsettled, and how fine a detail a view can show. Both are about how much is finally made clear.
Latin resolutio (a loosening, an unfastening), from resolvere (to loosen, to untie): re- (again) + solvere (to loosen); resolution is the untying of something knotted, whether that knot is a dispute or a blur too coarse to see through.
The settling of something unsettled, and how fine a detail a view can show. Both readings share the root's untying: each is about how much is finally made clear from what had been knotted or blurred.