Photoshop?

I recently saw a website with photos with a cool effect. It was the photo o an object which reflected part of its own image at the bottom of the picture. Like when you go to the fields and on the water of a lake you see the reflex of the mountain that is right in front of you. What is that effect? Can I do it in iphoto or a need photoshop?
Ijust find out that this effect is posible to make it in the tools of iWeb. Thanks anyway for your answers.