APNG
Animated Portable Network Graphics (APNG) is a file format which extends the Portable Network Graphics (PNG) specification to permit animated images that work similarly to animated GIF files, while supporting 24-bit images and 8-bit transparency not available for GIFs. It also retains backward compatibility with non-animated PNG files.
An animated PNG, or APNG, of a bouncing ball (displays as static image in some web browsers) | |
| Filename extension |
.png .apng |
|---|---|
| Internet media type | image/vnd.mozilla.apng, image/apng, image/png |
| Initial release | August 4, 2008 |
| Type of format | animated raster image format |
| Extended from | PNG |
| Open format? | yes |
The first frame of an APNG file is stored as a normal PNG stream, so most standard PNG decoders are able to display the first frame of an APNG file. The frame speed data and extra animation frames are stored in extra chunks (as provided for by the original PNG specification). APNG competed with Multiple-image Network Graphics (MNG), a comprehensive format for bitmapped animations which was created by the same team as PNG and is obsolete. APNG's advantage was the smaller library size and compatibility with older PNG implementations.
In a comparison made between GIF, APNG and lossless WebP, APNG had the lowest file size.