Is what the questioner did—leaving a job at an establishment that sells statues (while knowing that his work as an accountant does not involve touching the statues) and moving to another job with a lower salary—considered a correct decision, or is it an injustice to himself and his family?

What the questioner did by leaving the dubious work is absolutely correct, commendable, and will be rewarded, especially if the new work suffices for his necessities and those he supports. The questioner did not wrong himself and his household; rather, he treated them justly by seeking what is lawful and good, acting upon the hadith: "The lawful is clear, and the unlawful is clear." His outcome will be good due to his piety, in fulfillment of the Almighty's saying: "And whoever fears Allah – He will make for him a way out and will provide for him from where he does not expect." For whoever leaves something for the sake of Allah, Allah will compensate him with something better.