[automerger] Rework thumbnail cleanup am: f6b8f04d49 am: 490368eee9 am: 1579365b16 am: a7a1b17882 am: 7d2d26d85e am: 50945410d3 am: 2dfef2b080 am: de7103ca3f skipped: 0f0d9dab72 am: 61e28e4c2b  -s ours
am: 136eb5eac6  -s ours

Change-Id: Ib6c5bbf5f31e1d1623969b1cda31ab106ee09756