A tiny utility that encode GPG message into PNG format. (It actually encodes any binary that is throw into its stdin that has no 0x00)
License GPLv3
png++
If you are Arch Linux user, try out AUR/gpng-git.
cmake .
make
See gPNG -h
you shall see.
gpg --armor --export 0x8c18f6b0 | gpng g2p sample.png