png.txt for VISION
VISION support PNG image format through popular libpng (http://www.libpng.org/pub/png/libpng.html)
libpng is made availabe to Atari systems via a Shared Library (SLB).
This SLB is available for Mint and Magic Atari Oses.
- Download latest zlib and libpng libs available from http://tho-otto.de/download/zlib1211.zip and http://tho-otto.de/download/png1635.tbz
Under Mint:
- Extract ZLIB.SLB and PNGLIB16.SLB (68000 versions) to the SLB folder (usually c:/gemsys/slb but check SLBPATH environment variable in mint.cnf to make sure)
Under Magic:
- Extract ZLIB.SLB and PNGLIB16.SLB (68000 versions) to the SLB folder (usually c:/gemsys/magic/xtension unless SLBPATH is defined in MAGX.INF)

PS:
For more infomation about Shared libraries, visit http://toshyp.atari.org/en/00b017.html
Thorsten Otto page for libpng (among others) for Atari: http://tho-otto.de/sharedlibs.php