Unfortunately, it is still easy to steal pictures. All the images you view on your web browser go into a temporary folder on your hard drive, so you can find them if you go looking.
You can also press ALT + Print Screen and that will copy the entire browser window to your clipboard. You can then paste that image into any photo editing program.
I recommend watermarking any pictures you are afraid of someone stealing. You can also use check out
http://www.digimarc.com/. They have a digital watermarking program that puts an invisible watermark on your images. Whenever they are opened, they show up as being copyrighted. Each Digimarc customer has their own unique ID number for their images, and I believe you can track them anywhere on the web.