- RFC 2083 - PNG (Portable Network Graphics) Specification Version 1.0
- PNG (Portable Network Graphics) Specification 1.0 - 01/10/96
- Proposal for a Standard Color Space for the Internet
- TIFF-6. Final Specification. - 08/06/92 /compressed postscript/
- GIF-89a - 31/07/90
- GIF-87 - 15/06/87