Freely distribute a PDF that has unique border patterns so when people use/print it out and use that paper, and proceed to take a photo, the program can detect the borders and auto zoom in/out so you end up with a nicely fitted screen shot on the phone. Then users never worry about getting the heigh/width ratio right or bother with the cropping step. And you get to plaster your branding all over the desk of those that uses it :)