HTML 4 and HTML 5 includes Scalable Vector Graphics. This is an open human readable graphics standard. Most of the graphic standards such as GIF, Flash and JPG were proprietary standards designed to be written by machines. The inclusion of SVG could be a boon for independent web developers.
Most current browsers (Starting with Internet Explorer 8) support SVG. The market is now at a point where web developers can start including SVG with confidence that most browsers can display the graphics.
SVG Wow! (svg-wow.org) Site demonstrates advanced features of SVG.
SVG Tutorial - Jenkov (tutorials.jenkov.com) Jenkov has a useful tutorial with descriptions of each of the tags in SVG.