What is a PNG file?
PNG, Portable Network Graphics, is a lossless image format created in the mid-1990s to replace GIF. Lossless means the pixels you save are exactly the pixels you get back, no matter how many times the file is opened and re-saved. It supports full alpha transparency and up to 48-bit color, and every browser, operating system, and image editor on earth opens it.
PNG vs JPG
JPG discards detail to shrink photographs; PNG keeps everything. That makes PNG the right choice for screenshots, logos, icons, text, line art, and anything with transparency, and the wrong choice for photographs, where it produces files five to ten times larger than a JPG that looks identical. A 12-megapixel photo is 3 MB as JPG and 20 MB or more as PNG.
Working with PNG files
For the web, WebP gives smaller files than PNG with the same lossless quality and transparency. For icons, PNG is the source you turn into an ICO. For documents, several PNG screenshots can be combined into one PDF. And when a PNG screenshot is too big to email, converting it to JPG typically cuts the size by 80 percent or more.
Frequently asked questions
Does PNG lose quality?
No. PNG compression is lossless, like a ZIP file: the image is reproduced exactly.
Why is my PNG so large?
Because it stores every pixel exactly. Photographs and gradients compress poorly; converting them to JPG or WebP shrinks them dramatically.
Can a PNG be animated?
APNG exists but support is limited. For animation, GIF, WebP, or a video file are the practical choices.