MSpaint is not the best graphics editing program out there.. as we all know

-- But it is handy. Try this:
1. To start microsoft Paint, click 'Start', 'Programs', 'Accessories', then 'Paint'
2. Open the image file you wish to edit
3. Click the 'Image' Menu at the top and select "Stretch/Skew Image"
4. Choose a percentage figure to resize the image: to avoid distortion, choose the same percentage for horizontal and vertical stretch
5. Click "Ok"
6. Once you have the desired size, click 'File', then 'Save' or 'File', then 'Save As..' to prevent overwriting the original image
7. Second Method
* Select the entire image
* Hold down Ctrl and press - or + to resize the image.