Internet Explorer has had issues before with code execution vulnerabilities in .png files, which are also built using commands instead of dealing with images pixel-by-pixel http://www.microsoft.com/technet/security/bulletin/MS02-066.mspx I wouldn't at all be surprised if they are trying to cut down on support of command-based file formats to limit the number of attack vectors. An explanation of IE's support of SVG: http://wiki.svg.org/Internet_Explorer But Adobe also offers "SVG Viewer", but will remove it from their download page on January 1, 2009, (they cite the maturation of the market as the reason). There is an already promising alternative called Renesis, and with any luck, IE7 will either have support for a SVG viewer, or will come packaged with one (there is no shortage of people suggesting that to the IE7 team). Jake