Unofficial extension to the Animated Portable Network Graphic (APNG) format; contains multiple frames (.PNG images) used for an animation sequence; similar to an animated .GIF file, but also supports 24-bit images and 8-bit transparency.

Since the initial frame in a APNG file is stored as a normal PNG image, animated PNGs are backwards compatible with many applications that support PNG files. APNG files commonly use the standard ".png" extension.