clang++ main.cpp -o makepngb64
> makepngb64 2x2x2 0xaabb
2x2 PNG, filled with 0xaabb (r,g) for every 2-byte pixel:
iVBORw0KGgoAAAANSUhEUgAAAAIAAAACCAQAAADYv8WvAAAAEklEQVR4XmNctZuBgYmBgYEBAAvwAWmPyz9MAAAAAElFTkSuQmCC
> makepngb64 16x16x4 0xffffffff
16x16 PNG, filled with 0xffffffff (r,g,b,a) for every 4-byte pixel:
iVBORw0KGgoAAAANSUhEUgAAABAAAAAQCAYAAAAf8/9hAAAAIUlEQVR4XmP8DwQMFAAmBgrBqAEMDKNhMBoGoGw08OkAAGvKBBxbr9PgAAAAAElFTkSuQmCC