Animated Portable Network Graphics (APNG) is a file format that extends the Portable Network Graphics (PNG) format to support animated images. It retains backward compatibility with non-animated PNG files, meaning that viewers that don't support APNG will simply display the first frame as a static PNG image. APNG is particularly well-suited for animations that require lossless compression, such as interface animations or simple video clips. It supports 24-bit color and 8-bit transparency, providing high-quality visuals. APNG is often used as an alternative to GIF, offering better image quality and transparency support. The animation is achieved by storing multiple PNG frames within a single APNG file, along with control data that specifies the duration and display order of each frame. This allows for complex animations with varying frame rates and looping behavior. APNG is widely supported by modern web browsers and image viewers, making it a popular choice for creating animated content for the web.