The image is a visual of the message of the poster. It also makes the poster look interesting and more attractive.
Yes absolutely, The atomic bomb was catastrophic and showed the other nations the power USA held. They were being threatened and when push came to shove showed they were ready for whatever the threw at them tenfold. Japan was already showing advances on The United States and to keep them in their place the atomic bomb was unleashed. Trumans use of the atomic bomb was therefore highly justified.
New england did not have very good soil instead it was very rough and had many rocks in it. This is why they were not based on agriculture