How does Fitzgerald use details of setting and imagery to establish a mood in another chapter?

This extract takes place in Gatsby's Mansion. This extract has a completely different tone and natural environment compared to the "Valley of Ashes" in chapter 2. The author has quickly managed to create 2 really different moods in this book. He manages to create a dark and gloomy mood (for example, "The Valley of Ashes") and he also manages to create an uplifting, happy and a rich environment. In this short extract, we are able to see that Fitzgerald has managed to show-off the wealth of Gatsby. He has managed to do this by the use of imagery. For example, "And on Mondays eight servants, including an extra gardener, toiled all day with mops and scrubbing-brushes and hammers and garden-shears, repairing the ravages of the night before". This use of imagery has managed to show us how wealthy Gatsby is and how luxurious his life has become. This phrase shows us how he has at least 8 servants working at his disposal and that planning a party would be no trouble for him. From the extract, we are able to tell that this phrase show us how the author was able to create a wealthy and luxurious atmosphere using imagery which helps us realise how important imagery is while writing a piece of writing.