I create all of my paintings stretched onto a wooden board. The design is created with an excess of canvas in mind and I fill that extra canvas by painting to the edges. The design is created with the intention to be cropped upon final presentation. Each auction listing includes a second photo in the listing gallery which is a suggested crop as I intended the painting to be displayed. The full canvas that I paint includes an excess as part of the design to be cropped off when displayed. Below are photos illustrating how this works. 

Original canvas as it was painted stretched on a board

Full canvas image used for listing

Image of suggested crop as I intended the painting to be displayed when framed