Digital Photography

• Upload only low-resolution photos. That way, at least the pixel-pickers won’t be able to use your photos on print materials without your permission.
• Add a watermark. A watermark is just a bit of text that indicates that you hold the copyright to the photo, as shown here. You can create a watermark by simply adding some semi-transparent text to the image in your photo editor. Sure, it obscures part of your image, but if
  you keep the opacity of the text low enough, people can still get a good look at your picture. Just be sure to add the text to a copy of your original in case you want an unwatermarked version some day for your own use. And don’t place the watermark too close to the edges of the photo — that makes it too easy for would-be picture thieves to simply crop it away.
• Check your account settings. Many photo-sharing sites enable you to specify whether you want others to be able to download your images. Obviously, you want to disable that option.
• Choose a photo-sharing site carefully. Some sites are more concerned about protecting photographers than others and have more stringent processes in place to help discourage photo thievery. And read the membership terms of service carefully. At some sites, signing up for a membership gives the site unrestricted use of your images. I think that’s fine for sites that simply may want to use your photos in their own marketing materials — for example, an ad that touts their photo-sharing features. But some sites go farther and allow use of your photos by other entities. Not cool, IMHO.

If you’re a professional photographer (or hope to be), there are other, more sophisticated strategies you can try. But the bottom line is that a persistent hacker can get around any safeguard except clear watermarking, so the ultimate rule is, if you want to be absolutely sure your photos aren’t stolen, don’t make them publicly available.