How to pixelate a portion of an image or a picture using Microsoft Paint?

Microsoft Paint

Here's HOW!

1. Open the image or picture.
2. Choose "Select" and drag and drop the selection tool to the portion of the image or picture you want to pixelate. 
3. Click "Resize"
4. On the "Horizontal" change the value "100" to "5" then click "OK".
5. Click "Resize" again
6. On the "Horizontal" change the value "100" to "400" then click "OK".
7. On the "Horizontal" change the value "100" to "500" then click "OK".
8. Done.