[automerger] Rework thumbnail cleanup am: 82a2a87474 am: 97eb9d056a skipped: cb9dd5d0e6 am: ddfcb07714  -s ours
am: 7e7681f7c3  -s ours

Change-Id: Ic1dc057f8e32e2ef4ab09892f1d46a9f2bf89186