Overview
PNG was created in 1996 as a patent-free replacement for GIF, whose LZW compression was encumbered by patents at the time. It became a W3C recommendation and later the international standard ISO/IEC 15948.
PNG supports greyscale, palette-based (up to 256 colours) and truecolour images at up to 16 bits per channel, each optionally with a full alpha channel. Because it is lossless, what you save is exactly what you get back — ideal for images that will be edited again.
The APNG extension adds animation and is supported by all modern browsers, although many image editors still treat APNG files as a still image.
Advantages
- +Lossless: no quality loss, ever
- +Full 8-bit alpha transparency
- +Crisp edges and text
- +Universal support
- +Up to 16 bits per channel
Disadvantages
- −Photos are often 5–10× larger than as JPEG
- −No lossy mode in the standard (palette reduction is the usual workaround)
- −Animation (APNG) is poorly supported by editors
How PNG compression works
Each row of pixels is first “filtered”: one of five filters (None, Sub, Up, Average, Paeth) predicts every pixel from its neighbours and stores only the difference. The filtered data is then compressed with DEFLATE (LZ77 plus Huffman coding), the same algorithm used by ZIP. Optimisers such as OxiPNG try many filter and DEFLATE strategies to shrink files without changing a single pixel, and palette reduction (converting to 256 or fewer colours) can cut graphics files by 50–80% with little visible difference.
Common use cases
- Logos, icons and UI graphics
- Screenshots and diagrams
- Images that need transparency
- Intermediate files during editing
Browser and software support
Supported by every browser and image application. APNG animation works in all current browsers.
How to convert PNG
Use the converter at the top of this page: drop your file, choose an output format and download the result. Conversions run in your browser, so nothing is uploaded.
- JPG has no transparency. Transparent areas will be filled with the background colour.
Processed locally in your browser
PNG FAQ
Should I use PNG or JPG?
Use JPG for photographs and PNG for graphics with sharp edges, text, flat colours or transparency. A photo saved as PNG is lossless but usually far larger.
Why are my PNG files so large?
PNG is lossless, so photographic detail cannot be simplified away. Try PNG compression with colour reduction, or convert photos to JPG, WEBP or AVIF.
Does PNG support animation?
Yes, through the APNG extension supported by modern browsers. Many editors, however, only show the first frame.
Does converting to PNG improve quality?
No. PNG preserves the image exactly as it is; it cannot restore detail that a lossy format already discarded.