We estimate that over 70% of images produced by photographers are horizontal. This predisposition is natural: we see the world horizontally, as our eyes are positioned side by side and therefore we compose photos in the same way. Producing vertical images requires a lot more determination and effort, but the need for these images in stock photography is great, and the demand is not being met. Think that most on-line and off-line publications in the world are vertical. By simply shooting both a horizontal and vertical shot of your subject, you can easily increase the amount of images selected and significantly improve your sales opportunities. Give it a try!