Cropping & Aspect Ratio
The reason cropping may be required on your image is because the aspect ratio (shape) of your image is different than the aspect ratio of the print size chosen. For more information on aspect ratio, please have a look at our article on Understanding Aspect Ratio in our Help Centre.
You will have to crop your image to match the aspect ratio of your chosen size, or select a size that matches the aspect ratio of your image.
Cropping is performed in the Photo Image Editor after uploading your image. You can tell if your image is being cropped in the preview of your image by shifting the image around within the preview box. If the image moves within the box without any zoom applied, the image is being cropped. You can position your image within the box to apply your preferred cropping, or you can select a different size that matches, or is closer to, the aspect ratio of your image.