Dave -
This line of VBA does it:
ActiveChart.Export "C:\TEMP\TestChart.tif", "TIFF"
On my system I can also export using "GIF" and "PNG" formats, but it
choked on "BMP". "JPG" is also supported, but I advise anyone not to
use this, because it's only good for pictures with continuously shaded
regions, like photos and paintings. "GIF" is good for line drawings and
pictures with sharp color transitions.
- Jon