Sweet no identification of color space, gamma, and forced storage of the alpha channel. What a great format! /s<p>PNG is pretty stupid easy to parse and supports inline compression and multiple bit depths. If you want some uncompressed format that's easy to pipe and parse just use the NetPBM family.<p>Images are not just 2D arrays of pixels. There's extra data needed to tell the viewing system some of the image's provenance so it does so correctly.
This is exactly what you need for the intermediate stages of a video game asset pipeline where you have a prepared set of images ready to be re-encoded to compressed and packed textures: you don't want the overhead of decoding PNG at that stage, neither do you want a text parse like PPM. Bytes that can be used directly are good.<p>It's a hugely uninteresting format in most respects.
Why big-endian?<p>1. Optimizing for a big-endian CPU?<p>2. Optimizing for hex dump programs that don't have a setting for endianness?<p>3. Ideological purity?