Why firefox screenshot is not in jpg?

Hi Community,
My question is that why the firefox screenshot is not in JPG. JPG is best than others. And anyone can help me to get screenshots in JPG. Thanks

Technically speaking, PNG is superior than JPEG when it comes to screenshot. It handles detailed, high-contrast images better than JPEG because it can provide an almost pixel perfect copy of the screen, rather than compressing groups of pixels together.

However, if you need a JPEG version of your screenshot, you can always use a image converter software. Personally, I use GIMP (it’s free and open source).

Thanks for asking this question. I want to share my experience about screenshot of that pic which is capture during playing paintball games. Its in PNG but its so amazing and good quality.

jpeg is the worst for the web because of the obvious artifacts around text