I occasionally need to convert the background color of a particular image to be transparent so that the image looks better on medium with backgrounds of colors other than the image's original ...

You can make Microsoft Paint turn White background transparent using the Transparant Selection option. Check out this tutorial to learn how!

Do you want to make your Illustrator images have a transparent background?Learn how to make your white background transparent.

Amazon has been awarded a patent that details a system of taking photos against a white background, stock image pictured. The files even explain how best to set up a photography studio.