Copyright in most works of art, which includes writing, photography and digital images occur as the work is created. To put it as simply as possible, the second you click the shutter button, the resulting image belongs to you.
No formal registration is needed in more than 140 countries in the world, to receive basic legal protection. But regardless, if you do feel that you don‘t understand certain legal points, you would be well advised to speak to your legal advisors.
Although the law protects your copyright from the moment the shutter is released and there is no other formalities to be observed, I would strongly advise that you mark every single photograph with the word “copyright” followed by your name, or use the international copyright symbol followed by your name: © – TJ Tierney (for example)
When you do sell an image understand the reproduction rights. If you agree to “single reproduction rights” you are granting the magazine or publisher rights to use the image once. If they decide to use the same print in a few months time, you’re entitled to further reproduction fees.
Don’t ever sell your images as “royalty free”. You may receive an “ok payment“, but the publisher that has paid for the royalties can sell your images to whoever he wants; and you won’t receive a single cent.
If in three months time you see an image that belongs to you on the cover page of some magazine; and know full well that they are in breach of your copyright, don’t be afraid to send them an invoice, adding on a little extra for their cheekiness. Let them know that you know the law and that if the payment isn’t received by a certain date that further action will be taken; you’ll probably receive a serious response quickly – preferably you’ll receive a check.