Picture should be big enough to tell the days news and give readers a sense of story’s importance
If your photo is your dominant piece of art and it is horizontal, plan to run it at least 3 columns wide. If your dominant photo is vertical, run it as least two-three columns wide. Vertical photos more than three columns wide take up massive amounts of space and are rarely used except in special layouts.
If the photo is to be used as secondary art – that is the second or third photo on the page – it should be large enough to make visual sense but not so large that it competes with the dominant photo for the viewer’s eye. If the secondary photo is horizontal, size it for two columns. Larger will work only if the dominant photo is four or five columns wide. If a secondary photo is vertical, try it in one or two columns.