You've probably heard that several times by now. Well, I'm going to teach you how to do it. Just follow what I say.
Pick an image. I picked this one:

Now, open up Microsoft Paint. START>>PROGRAMS>>ACCESSORIES>>PAINT. After that, copy the image and paste it into paint. Make the canvas, (the white part,) longer. You should see this:

Select a little part of the bottom with the crop tool (square with dotted lines.) Then, pull it down. You should end up with a picture like this:

You see how it's pixelized? We're going to fix that.
Select some of the pixelized picture at the top and pull it down again. Do it over and over until everything is straight. It should look like this:

See? You're done! Nice and pretty huh? Now all you have to do is throw together some stuff and it should look great! I hope you enjoyed this Tutorial!
~Mariah