How does Dorianne Laux use imagery in For the Sake of Strangers?

Imagery:

We rise and gather momentum, the dull strength
that pushes us through crowds.

A woman holds the glass door open,
waits patiently for my empty body to pass through.
All day it continues, each kindness
reaching toward another – a stranger
singing to no one as I pass on the path, trees
offering their blossoms, a retarded child
who lifts his almond eyes and smiles.