More LibPng!

http://old.nabble.com/problem-using-png_set_tRNS-td13425379.html
the only way to add a transparent color using is ... to manually search and swap in IDAT.

PNG is the worst graphics format ever! Use GIF or TGA where possible.

>>1
Wrong. PNG supports 32-bit RGBA. Note the A for Alpha channel. You implement full transparency by setting the desired pixels to have an Alpha component of zero.

PNG is in fact superior, as it supports fine-grained transparency as well as a full 8-bits of translucency.

Do not use GIF or TGA.