English ▾
Free, Fast & Secure Online Tools
The logo in your browser tab is probably a PNG. The icons in the app you’re using right now are likely PNG. When a designer sends you an image “on a transparent background,” it’s almost certainly a PNG. Portable Network Graphics is the web’s essential lossless image format, and its two defining capabilities — lossless compression and full alpha-channel transparency — make it irreplaceable for a wide range of use cases that JPEG simply cannot handle.
PNG was not a natural evolution — it was created to solve a legal crisis. In 1994–1995, Unisys Corporation began enforcing a patent on the LZW compression algorithm used inside the GIF format, demanding licensing fees from software that created or displayed GIF files. The internet community was outraged by the idea of paying royalties to use a common image format, and a group of developers set out to create an open, patent-free alternative.
The design goals were deliberately ambitious: PNG should be better than GIF in every measurable way except animation (which was intentionally left out, kept as a deliberate scope boundary):
The PNG specification was published in 1996. It became an ISO/IEC international standard (ISO/IEC 15948) in 2004. GIF animation support was deliberately excluded — PNG would do one thing exceptionally well. (The community later developed APNG as an animated PNG extension, but it was never part of the official spec.)
PNG uses the DEFLATE compression algorithm — the same algorithm used in ZIP files. DEFLATE is lossless: the pixel data before and after compression is mathematically identical. The algorithm finds more efficient ways to represent the same information; it never discards any of it.
This is a fundamental difference from JPEG. JPEG achieves small file sizes by throwing away image data that human perception is unlikely to notice. PNG achieves compression by finding redundancy and encoding it more efficiently, but the original pixel values are always fully recoverable.
PNG compression is particularly effective on:
For photographs, PNG compression is relatively inefficient — photographs have significant variation between adjacent pixels, leaving little redundancy for DEFLATE to exploit. A PNG photograph is typically 3–5x larger than an equivalent JPEG.
PNG’s most practically important feature is the alpha channel. Each pixel in an RGBA PNG has four values: Red (0–255), Green (0–255), Blue (0–255), and Alpha (0–255). An alpha value of 0 is fully transparent, 255 is fully opaque, and intermediate values create partial transparency.
This capability enables design effects that are impossible in JPEG:
This is one of the most common questions about PNG. The answer lies in the nature of the compression methods. JPEG’s lossy compression can discard enormous amounts of data, achieving extreme size reductions. PNG’s lossless compression must preserve all data; the only savings come from encoding redundancy more efficiently.
For a 1920×1080 landscape photograph:
PNG is the right format where pixel accuracy matters. JPEG is the right format where file size must be minimized for photographic content.
PNG supports several color modes to suit different content types:
Do it in your browser — the file never leaves your device: Image Convert