Microsoft Adds Photoshop-Like Background Removal Feature to Paint
Microsoft Paint is not dead. In fact, it's getting a background removal tool à la Photoshop.
How to Remove a Background in Photoshop
Using Photoshop to remove the background in an image so that you can replace it is one of the most frequent things for which it was used, and might still be. The actual placing of a new image for a background is relatively easy. The heavy lifting comes from making a good selection of your subject as this will be used to remove the unwanted background for replacement.