[automerger] Rework thumbnail cleanup am: 82a2a87474 am: 97eb9d056a skipped: cb9dd5d0e6 am: ddfcb07714  -s ours am: 7e7681f7c3  -s ours
am: 36f77be954  -s ours

Change-Id: I3aed2cd01667f1befe5bb401cef41922f3133da7