Tue Nov  2 22:50:31 GMT 1999 Andy Thomas <alt@gimp.org>

	* app/undo.h
	* app/undo.c
	* app/undo_history.c
	* pixmaps/question.xpm

	Fixed undo history so it shows a dummy image if the preview
	image has not already been generated. The actual image
	could probably do with an artists hand ;-)
	Also mask operations are shown as such in the previews.

	* app/lc_dialog.c

	Fixed rounding error in preview when width << height.

	* plug-ins/common/jpeg.c

	Always freeze the undo stack for any of the image export types.
	Anyone know why this was not the case to start with?