The correct way to say PNG is actually just "ping". It was created in the mid-90s by a group of developers who wanted a patent-free format to replace GIFs.
Beyond just being a picture, files like yours are often used in advanced technical research. For instance, the project uses deep learning to "read" mobile UI screenshots and summarize their content into natural language phrases. Fun Fact: The "Ping"
Every single pixel on your screen is captured exactly as it appeared. When you save a screen2.PNG, no data is "thrown away" to save space.