
From: http://oakdome.com/k5/tutorials/green-screen/
Times are tough, the new buzzword is "Stay-Cations". This tutorial will show you how to use a FREE photo editor to put yourself in your dream vacation location.
This tutorial is for Windows users.
I have done this activity with 4th and 5th graders. Preparation is key. Have everything installed and ready to go on the computers. Have a good green screen, a selection of background pictures, and a camera ready to go. The kids have a great time with this one.

Things you will need:
1. Picture of yourself in front of a solid green background.
2. Paint.NET free photo editor (A Windows application) (Download)
3. Chromakey plugin for Paint.net (Download)
Step One:
Install Paint.NET. Read the requirements, you may need to download an additional supporting program from Microsoft called the .Net Framework 3.5 SP1 (Free).
If you have difficulty installing the .Net file, try this link for the full download (here).

Step Two:
Install the ChromaKey Plugin. Once you download the ChromaKey plugin, unzip the file and copy the ChromaKeyPlugin.dll file to the Effects folder of your Paint.NET program folder.
Here I've copied the plugin to the default Paint.NET program installation at C:\Program Files\Paint.Net\Effects. If you had Paint.Net open, close it and restart it so it can find the plugin.

Step Three:
Place the following two pictures on your desktop:
You with a green screen background and a picture of your dream vacation location.
Open Paint.NET.

Step Four:
Drag and drop the VACATION picture onto the PAINT.NET canvas. In the Drag and Drop dialog box choose "Add into layer(s)".

Here is the result. If needed, adjust the size of the vacation picture or the canvas size from "Image" on the toolbar.

Step Five:
Drag and drop your green screen picture onto Paint.NET canvas, again choosing "Add into layer(s)" in the Drag and Drop dialog box.
On the menu bar choose Effects > Photo > Chroma Key.

Step Six:
The ChromaKey dialog box offers sliders to adjust the amount of green color being keyed out. Adjust to suit your needs. Notice that there is an option to key out a blue background (blue screen).
Final result:

DONE.