Issue #2390745 by slashrsm: Implement MediaTypeInterface::thumbnail().
Issue #2390745 by slashrsm: Use maxres image.
Issue #2390745 by slashrsm: Fix typo.
Merge branch '8.x-1.x' into 2390745
Merge pull request #2 from slashrsm/2390745

Implement MediaTypeInterface::thumbnail()