How does Katherine Mansfield use imagery in The Garden Party?

Masfield uses images of light and darkness to illustrate the contrasting worlds in which the characters live.

The world of the Scott family:

Now the broad road was crossed. The lane began, smoky and dark. Women in shawls and men's tweed caps hurried by. Men hung over the palings; the children played in the doorways. A low hum came from the mean little cottages. In some of them there was a flicker of light, and a shadow, crab-like, moved across the window.

The world of the Sheridans:

And after all the weather was ideal. They could not have had a more perfect day for a garden-party if they had ordered it. Windless, warm, the sky without a cloud. Only the blue was veiled with a haze of light gold, as it is sometimes in early summer.