That is a very stirring photo ... speaks to the supremacy of the US in the Pacific Campaign. Distances and scales involved, this campaign is arguably the most complicated campaign in human history. Made more impressive becuase the campaign went from idle in neutral to turbo ovrrdrive in only four years.
A lot of historians have questioned the need to take Iwo citing various factors. I personally think it's a matter of 20/20 hindsight as the the first night raids from the Marianas occurred after Iwo had been invaded.