Hi Owen,

Thanks for nudging me on how this is done... I added that feature a
long time ago, expecting that I'd make it easier to get at. Then I
failed to do so. To expand on your post:

To delete a downloaded DSS image, first right-click on any of the
corners of the image. (At times, the corners can be not very obvious.
It helps to change the background color, or toggle the "Invert
Images" check-box in the Extras... DSS/RealSky Images dialog.) You'll
get a dialog giving the name of the FITS file and its size in pixels,
and the usual four buttons: OK, More Info, Display, Next. Click OK.

Now hit Shift-F8. You will get a box that asks for the "File name?"
Type "del" and hit Enter or click OK. The file will be deleted.

-- Bill