2004-02-10  Michael Natterer  <mitch@gimp.org>

	* app/core/gimpviewable.[ch]: added new function
	gimp_viewable_get_dummy_preview() which currently returns a
	completely white and opaque TempBuf of the requested size.  Added
	this useless function because this is the place where to implement
	a nicer preview if someone volunteers.

	* tools/pdbgen/pdb/drawable.pdb
	* tools/pdbgen/pdb/image.pdb: use the new function if
	gimp->config->layer_previews is FALSE instead of returning no
	preview at all. Fixes bug #112012.

	Cleaned up the preview functions a bit and raised
	the limit for drawable previews from 128x128 to 256x256.

	* app/pdb/drawable_cmds.c
	* app/pdb/image_cmds.c
	* libgimp/gimpdrawable_pdb.c: regenerated.