APNGb

APNGb is a macOS utility that builds animated PNG (APNG) files from a sequence of PNG frames and can also extract the individual frames from an existing APNG. The assembling workflow includes options to adjust frame delays, choose playback settings, and apply a range of optimization and compression techniques such as inter‑frame alpha blending, dirty transparency, palette reduction, and various compressors (zlib, 7zip, Zopfli). The disassembly process parses APNG chunks, remuxes them into static PNG images, and reconstructs full‑size frames using standard libpng decoding.

The application targets users who need to create or edit animated PNGs on macOS 10.11 and later, offering a graphical front‑end to the underlying command‑line tools APNG Assembler and APNG Disassembler developed by Max Stepin. It is open‑source under the MIT license, while the bundled assembler and disassembler components are released under the zlib/libpng license. The software emphasizes lossless animation with higher color depth and transparency support compared with GIF, while aiming to keep file sizes small through its optimization pipeline.