breaking changes for v7:

• ImageElements: replace all the usesX (usesObjectFit, usesPixelArtScaling, etc) boolean properties in ImageElements with their raw property equivalents instead
• ImageElements: Make naturalWidth/naturalHeight optional in ImageElements, don't set for <picture> images until we're sure (ref Displays images with inappropriate size #11450)
• ImageElements: Remove duplicated resourceSize in ImageElements that duplicates network record property.
  • PR in the works.

ref #11207