As scout is drifting off to sleep two images come into her mind what are they and why do they cause her to cry

From the text:

Atticus killed the engine in the driveway and coasted to the carhouse; we went in the back door and to our rooms without a word. I was very tired, and was drifting into sleep when the memory of Atticus calmly folding his newspaper and pushing back his hat became Atticus standing in the middle of an empty waiting street, pushing up his glasses.  The full meaning of the night’s events hit me and I began crying. Jem was awfully nice about it: for once he didn’t remind me that people nearly nine years old didn’t do things like that.