Images, photos & graphics are most effective online when they are created in pixels at 72 dpi resolution.
The correct size to allow for proper display is 720 x 400 pixels.
When viewed as a sidebar on all pages, except the Inside Look page, the image is 720 x 400 pixels.
When the image is viewed in the Inside Look section, the image is squared automatically. Both sides of the image are cropped equally to a 400 x 400 pixel square.
Example of the automatic crop.