The frame speed data and extra animation frames are stored in extra chunks (as provided for by the original PNG specification).
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. It also retains backward compatibility with non-animated PNG files. Image/, image/apng, image/pngĪnimated 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.
