2004-11-18  Sven Neumann  <sven@gimp.org>

	* app/file/file-open.c (file_open_thumbnail): check the number of
	return values. Only retrieve width and height if the thumbnail
	load procedure does actually provide such this information.

	* plug-ins/common/postscript.c: added a procedure to loads
	thumbnails.  For now it only renders the first page of the
	document at low resolution. It should be extended to load an
	embedded thumbnail if available.

	* plug-ins/common/jpeg.c
	* plug-ins/common/svg.c: no need to register a menu label for the
	thumbnail loaders. Allocate the return_vals array large enough to
	hold all return values.