Photoshop is cheap for how powerful it is.
Photoshop is easy to use if you know how to use it.
Photoshop would be expensive if you're just going to use it to watermark photos.
Even if you do watermark the photos, there is no way for you to use Photoshop to deter people from saving that image from the website onto their hard drive.
It is nearly impossible for you to stop people from saving the photos they see on your website onto their computer. Scratch that- it IS impossible. You can watermark and put up copyright restrictions and deactivate right clicking all you want, that still wont stop someone from hitting the "print screen" button on their keyboard and pasting that into MS Paint or, you know, Photoshop.
The only way to keep a photo from being stolen is to keep it off the internet. It's kind of the same thing as keeping your car from being broken into- lo-jack and car alarms and locked doors wont keep someone with a crowbar from putting out a window. The best you can do is just to watermark the photos, throw a copyright clause at the bottom of the page and hope for the best. And as Steve Hahn has mentioned numerous times in this forum over the years, you should consider sending all of your photos in to the US copyright office from time to time to prove ownership of the photo. Perhaps he will be kind enough to provide that address again here.
(Message edited by scott_a on May 23, 2008)