Scale Option is how your image fits within the print area of the poster.
The entire image will be placed within the print area and centered. If the image is smaller or larger, it will be scaled up or down to fit. 100% of the image will be printed and the aspect ratio will be maintained.
If the aspect ratio of the image and poster differ, some white area may show. For instance, if you selected an 18" x 24" poster and uploaded an 18" x 18" image, the image would be centered on the page with 3" of white space at the top, and 3" of white space at the bottom.
The image will be scaled up or down to cover the print area with the image. Some of the image may be cut off, but the aspect ratio of the image will be maintained.
The image size will be matched to the poster size. 100% of the image will be printed. The aspect ratio will NOT be maintained.
The image will print at it's native size, regardless of the poster size selected.
BLEED is highly suggested if you use this option.