Many magazines buy shots of their basic subject matter year-round. You don't have to simply guess what editors are looking for. Many magazines offer photographers' guidelines that list upcoming articles and the types of photos that will be required. These guidelines will tell you when photos must be submitted for each issue. You may even make more money by selling your photos separately than if you combine them with an article.
Larger magazines pay more, of course, but also expect top quality.
Finally, you may find that a photo submission can lead to an article assignment. This article originally appeared as part of Moira Allen's Freelancing 101 column on Inkspot. All rights reserved.