PNG killed GIF’s patent monopoly — but not its utility.
PNG is a specification, not a product. It is a response to legal constraint, not technical ambition. It works where it was designed to work — and fails where it was never meant to go.
PNG exists because GIF was patented — not because it was technically inferior.
2:29
How Compression Actually Works
Filtering + DEFLATE makes PNG lossless, predictable, and royalty-free — no black-box tuning.
3:44
What Fits Inside
One image. One chunk structure. Full support for alpha — but no animation, no layers, no metadata beyond what fits in chunks.
5:26
The Long Road to Standard
W3C approval in 1996, RFC in 1997, ISO in 2004 — standardisation was slow, deliberate, and consensus-driven.
Worth your time?
Yes. Study the whole thing.
4.5/ 5
What works
lossless compression
alpha transparency
chunk extensibility
patent-free deployment
What does not
animation
lossy compression
multi-image storage
Study it if
web developers
archivists
open-source toolchains
Skip it if
video engineers
real-time streaming pipelines
embedded systems with tight memory budgets (unless DEFLATE is already present)
The written brief1 min read
What it is and the problem it solves
PNG is a raster-graphics file format designed as a non-patented replacement for GIF. It solves the problem of licensing risk and limited transparency in GIF while preserving lossless fidelity.
How it works
PNG uses a two-stage compression process: filtering to predict pixel values, then DEFLATE — a non-patented algorithm combining LZ77 and Huffman coding. A PNG file stores one image as an extensible sequence of chunks containing pixels, comments, and integrity checks.
What works
PNG reliably supports palette-based, grayscale, and RGB/RGBA images. Its chunk-based structure enables forward compatibility. DEFLATE delivers consistent lossless compression without royalties.
What does not
PNG does not support animation, nor does it offer lossy compression options. It was never intended to replace JPEG for photographs or GIF for animated sequences.
What it changes
PNG changed how web graphics handled transparency and patent-free interchange. It displaced GIF for static images requiring alpha channels, but did not eliminate GIF’s dominance in simple animations or legacy use.
Is it worth your time
Yes — if you need lossless compression, transparency support, or interoperability without patent risk. It costs nothing to run. No runtime overhead beyond standard DEFLATE decoding.