Merge "Update documentation for Image to be clear on valid format enums." into tm-dev am: 82409626b9

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/17006063

Change-Id: I6e17ff431cb69a5a2d602526c754185c97a8ee69
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>