2004-10-08  Sven Neumann  <sven@gimp.org>

	* app/config/gimpcoreconfig.[ch]
	* app/config/gimprc-blurbs.h: added new gimprc option
	"thumbnail-filesize-limit" that allows to control the maximum
	filesize for automatic thumbnail creation.

	* app/dialogs/preferences-dialog.c: added a GUI for it, needs
	review.

	* app/core/gimpimagefile.[ch]: minor cleanups. Moved call to
	gimp_thumbnail_peek_image() from gimp_imagefile_save_thumb() to
	 gimp_imagefile_save_thumbnail() to avoid it being called twice.

	* app/file/file-utils.[ch]: export utility function
	file_utils_find_proc_by_extension() that allows to check for a
	file plug-in by looking at the filename extension only.

	* app/widgets/gimpthumbbox.[ch]: automatically create or update
	thumbnails for image files with a known extension that are smaller
	than "thumbnail-filesize-limit".  Fixes bug #137176.