Request: ppm or png input/output

Currently the input/output file formats are headerless raw image buffers in somewhat exotic pixel formats.
It would be convenient if the input/output can be done using 16-bit ppm (or float32 pfm) buffers, or even better, using 16-bit png files with proper colorspace tagging.

E.g. it would be very convenient to have a simple decode tool that takes an UltraHDR JPEG as input and produces a 16-bit PNG file as output (properly tagged with a cICP chunk or with an ICC profile containing a cicp tag), such that both images render in the same way when viewed in Chrome.
(and a simple encode tool that does the same thing in the other direction)