I don't see block.cover documented http://developer.thegrid.io/api.html#content-management-item
Is there a key for faces + saliency bbox, or do I need to derive that? @automata
I need to decide where/how to save user-defined focus rectangle
block.metadata.coverPrefs.scene -- ok?
{x,y,width,height} -- top-left, bottom-right points of original pixels ok?