Here's a small tutorial on how to make an avatar with only MSPaint and IrfanView.
1. First off you'll need one more aditional program. Don't worry, it's safe and free.
Go to
http://www.irfanview.com and download the program. Just be sure to read everything in installation proces so you'll avoid any unwanted toolbars.
2. Open your image in MS paint and crop it. Heigt and width must be the same. It doesn't matter how big it is now.
3. Save and open the cropped image in IrfanView. There are some ready effects you can apply but you can also change colors and contrast in Image>Color Correction. I brightened my image a little here.
4. After you're happy with colours and effects, to to Image>Resize/Resample and resize it to avatar size (I usually do 150X150 avatars). Save the edited image.
5. I opened my avatar in MSPaint again to add a small border.

And it's done! You can save your images as PNG so they won't pixelise that much as JPEG format.
