Additional Ways to Protect Your Photos
Adobe Photoshop, Aperture, Lightroom, and other editing and cataloging programs allow you to imbed your copyright and contact information in the metadata of the photo file. For example, after you have opened your photo in Photoshop, select File, and then File Info, and fill in the copyright information there. The other editing and cataloging programs work similarly. Note that this metadata will be removed by using the "Save for Web" utility.
Another good way to include your copyright and contact information and to protect your photo from being copied without permission is to put a watermark on the image. This function puts the copyright notice directly on the photo so that unauthorized use is impaired and the viewer is put on notice of copyright protection. Include your contact information, as well, for potential customers. The steps on how to do put a watermark on your slideshow photos in Lightroom are available at Lightroom News. Further, watermarks are a good idea because they can lead to significant damage awards when the photos are infringed. See my blog post on the details.
While sophisticated computer users can override these efforts to protect your work, they will thwart many unauthorized uses of your photos or give interested customers your contact information. Although infringements will never be stopped, photographers should do what they can to prevent them.
Take my advice; get professional help.