SVG Import

This is an absolute must have extension. SVG is a free format for scalable vector graphics. Vector graphics can be resized and rotation can be changed without loose of quality as you will experience with normal bitmaps. In the future, SVG is expected to be integrated in OpenOffice.org but until then this extension is what you need.

SVG-Import: http://www.ipd.uka.de/~hauma/svg-import
OpenClipart: http://www.openclipart.org/