A easy and less intrusive way of adding a watermark to your photos in Photoshop is to add a watermark using simple to follow instructions.
Instead of watermarking your photos with the name of your website, watermark them with the address of your website. For example: "YourCompany.com". That way, if the photo should get out of your control and/or you end up posting it on someone elses website, people will know where it came from and where to find you in particular without having to do any research on your company name.
Watermarking won't eliminate the possibility of people lifting your photos, just deter them a little.
Another time this might be useful is if someone is shopping for a photo and prints a whole bunch out to show a friend. Yours would be easy to trace back to your site if the address of your website was watermarked on it and it might spread awareness of your amazing skills and offerings in the process.
Just imagine if you had one of your framed photo on your wall at work and it had your website address on it. People, who might otherwise never even assume you were the photographer or know where you got the photo could just jot down you website address and then checkout your website on their own.
Reduce the Resolution of the Image
Another technique I often see is to simply avoid making the full resolution version of your photo available on your website. Depending on your intention, preferably 640×480 or 800×600 at the very most available on your website. Smaller sizes are only valuable as thumbnails as people won't be able to see any details in the image. Any larger and people won't need to purchase it from you. They'll be able to print it on their own.
Computer Wall Paper
When it comes to computers, Wallpaper is the image that appears on your desktop. In order for it to appear nicely, images will need to be of a higher resolution. Keep in mind that there are generally two formats of screens available. The old 4:3 ratio size and the newer 16:9 widescreen. If possible, it's always nice to make both formats available for download so that people can get the size that best fits their screen.