Your images should be a LARGE, horizontal layout, preferably 900 pixels wide by 600 pixels high so your listing will look its best.
Other acceptable sizes (the larger, the better):
1500 x 1000
6000 x 4000
Free online resize / crop tool is available at http://picresize.com
(Example of image size: 900 x 600 pixel)
For additional assistance, please contact email@example.com or call 954-767-2483