One of the best aspects of the PNG format is that it facilitates transparent images, which is helpful in many instances. For example, a website creator may want to have a logo on their page that doesn't hide the background. Transparency is also useful when adding pictures to a web page that need to work in light mode and dark mode.
The PNG format was introduced on January 10, 1996, and later defined in RFC 2083 in March 1997. PNG was created to replace GIF after Unisys and CompuServe announced on December 24, 1994, that they expected licensing fees for any software that creates and displays GIF images.
Should I save as PNG-8 or PNG-24?
Some users are confused when they are presented with the option to save an image as PNG-8 or PNG-24. The PNG-8 format is a lot like a GIF. We suggest using it if you're concerned about file size and the image has no transparency. If the image contains transparency and will be placed on different colored backgrounds, we suggest using PNG-24.