Spatial partitioning for Chipping with Boxes

There are seriously better ways to handle chipping images and associating bounding boxes to them. Spatial partitioning could offer speedups, but suggestions of alternatives would be nice as well.

Start by reviewing the existing image chipping and bounding-box association implementation, then compare it with spatial partitioning and other suggested alternatives. The issue does not name files, tests, or an entry point, and completion criteria are not defined beyond finding a potentially faster approach.

Written by the indexing model from the issue text.