4t HIT Mail Privacy Lite allows you to send and receive data securely hidden in images of various types (gif, jpeg, tiff, etc). This application uses a strong encryption algorithm to make communications secure.
Links
[1] https://www.pambazuka.org/author/contributor
[2] https://www.pambazuka.org/taxonomy/term/3305
[3] https://www.pambazuka.org/article-issue/92
[4] https://www.pambazuka.org/category/ict-media-security
[5] http://www.pambazuka.org/en/category.php/internet/12113