diff --git a/TODO b/TODO
index 52975e92..f68328ed 100644
--- a/TODO
+++ b/TODO
@@ -1,3 +1,8 @@
+- read_vips() in im_open.c:179 needs moving to format and breaking into is_a,
+  header, load and save, as tiff etc.
+
+  make im_file2vips, im_vips2file?
+
 - pluggable formats
 
   for each format, store:
diff --git a/include/vips/dispatch.h b/include/vips/dispatch.h
index 18cc4170..48bfca51 100644
--- a/include/vips/dispatch.h
+++ b/include/vips/dispatch.h
@@ -300,6 +300,12 @@ im_function *im_find_function( const char *name );
 im_package *im_find_package( const char *name );
 im_package *im_package_of_function( const char *name );
 
+/* Map over and find formats.
+ */
+void *im_map_formats( VSListMap2Fn fn, void *a, void *b );
+im_format *im_format_for_file( const char *filename );
+im_format *im_format_for_name( const char *filename );
+
 /* Allocate space for, and free im_object argument lists.
  */
 int im_free_vargv( im_function *fn, im_object *vargv );
diff --git a/libsrc/format/format_dispatch.c b/libsrc/format/format_dispatch.c
index 36938d8c..a48ee804 100644
--- a/libsrc/format/format_dispatch.c
+++ b/libsrc/format/format_dispatch.c
@@ -418,5 +418,124 @@ im_package im__format = {
 	list
 };
 
+/* Suffix sets.
+ */
+static const char *tiff_suffs[] = { ".tif", ".tiff", NULL };
+static const char *jpeg_suffs[] = { ".jpg", ".jpeg", ".jpe", NULL };
+static const char *png_suffs[] = { ".png", NULL };
+static const char *csv_suffs[] = { ".csv", NULL };
+static const char *ppm_suffs[] = { ".ppm", ".pgm", ".pbm", NULL };
+static const char *exr_suffs[] = { ".exr", NULL };
+static const char *analyze_suffs[] = { ".img", ".hdr", NULL };
+static const char *magick_suffs[] = { NULL };
 
+/* VIPS image formats.
+ */
+static im_format jpeg_desc = {
+	"jpeg",			/* internal name */
+	N_( "JPEG" ),		/* i18n'd visible name */
+	0,			/* Priority */
+	jpeg_suffs,		/* Allowed suffixes */
+	im_isjpeg,		/* is_a */
+	im_jpeg2vips_header,	/* Load header only */
+	im_jpeg2vips,		/* Load */
+	im_vips2jpeg		/* Save */
+};
 
+static im_format tiff_desc = {
+	"tiff",			/* internal name */
+	N_( "TIFF" ),		/* i18n'd visible name */
+	0,			/* Priority */
+	tiff_suffs,		/* Allowed suffixes */
+	im_istiff,		/* is_a */
+	im_tiff2vips_header,	/* Load header only */
+	im_tiff2vips,		/* Load */
+	im_vips2tiff		/* Save */
+};
+
+static im_format png_desc = {
+	"png",			/* internal name */
+	N_( "PNG" ),		/* i18n'd visible name */
+	0,			/* Priority */
+	png_suffs,		/* Allowed suffixes */
+	im_ispng,			/* is_a */
+	im_png2vips_header,	/* Load header only */
+	im_png2vips,		/* Load */
+	im_vips2png		/* Save */
+};
+
+static im_format csv_desc = {
+	"csv",			/* internal name */
+	N_( "CSV" ),		/* i18n'd visible name */
+	0,			/* Priority */
+	csv_suffs,		/* Allowed suffixes */
+	NULL,			/* is_a */
+	im_csv2vips_header,	/* Load header only */
+	im_csv2vips,		/* Load */
+	im_vips2csv		/* Save */
+};
+
+static im_format ppm_desc = {
+	"ppm",			/* internal name */
+	N_( "PPM/PBM/PNM" ),		/* i18n'd visible name */
+	0,			/* Priority */
+	ppm_suffs,		/* Allowed suffixes */
+	im_isppm,			/* is_a */
+	im_ppm2vips_header,	/* Load header only */
+	im_ppm2vips,		/* Load */
+	im_vips2ppm		/* Save */
+};
+
+static im_format analyze_desc = {
+	"analyze",		/* internal name */
+	N_( "Analyze 6.0" ),	/* i18n'd visible name */
+	0,			/* Priority */
+	analyze_suffs,		/* Allowed suffixes */
+	im_isanalyze,		/* is_a */
+	im_analyze2vips_header,	/* Load header only */
+	im_analyze2vips,	/* Load */
+	NULL			/* Save */
+};
+
+static im_format exr_desc = {
+	"exr",			/* internal name */
+	N_( "OpenEXR" ),	/* i18n'd visible name */
+	0,			/* Priority */
+	exr_suffs,		/* Allowed suffixes */
+	im_isexr,			/* is_a */
+	im_exr2vips_header,	/* Load header only */
+	im_exr2vips,		/* Load */
+	NULL			/* Save */
+};
+
+static im_format magick_desc = {
+	"magick",		/* internal name */
+	N_( "ImageMagick-supported format" ),	/* i18n'd visible name */
+	-1000,			/* Priority */
+	magick_suffs,		/* Allowed suffixes */
+	im_ismagick,		/* is_a */
+	im_magick2vips_header,	/* Load header only */
+	im_magick2vips,		/* Load */
+	NULL			/* Save */
+};
+
+/* Package up all these formats.
+ */
+static im_format *format_list[] = {
+	&csv_desc,
+	&jpeg_desc,
+	&magick_desc,
+	&png_desc,
+	&exr_desc,
+	&ppm_desc,
+	&analyze_desc,
+	&tiff_desc
+};
+
+/* Package of format.
+ */
+im_format_package im__format_format = {
+	"format",
+	IM_NUMBER( format_list ),
+	format_list
+};
diff --git a/libsrc/iofuncs/im_open.c b/libsrc/iofuncs/im_open.c
index fb712565..e0ee4903 100644
--- a/libsrc/iofuncs/im_open.c
+++ b/libsrc/iofuncs/im_open.c
@@ -225,6 +225,30 @@ read_vips( const char *filename )
 	return( im2 );
 }
 
+/*
+		else if( im_isvips( name ) ) {
+			if( mode[1] == 'w' ) {
+				if( !(im = im_init( filename )) )
+					return( NULL );
+				if( im_openinrw( im ) ) {
+					im_close( im );
+					return( NULL );
+				}
+				if( im->Bbits != IM_BBITS_BYTE &&
+					im_isMSBfirst( im ) != 
+						im_amiMSBfirst() ) {
+					im_close( im );
+					im_error( "im_open", _( "open for read-"
+						"write for native format "
+						"images only" ) );
+					return( NULL );
+				}
+			}
+			else 
+				im = read_vips( filename );
+		}
+ */
+
 /* Delayed save: if we write to TIFF or to JPEG format, actually do the write
  * to a "p" and on preclose do im_vips2tiff() or whatever. Track save
  * parameters here.
@@ -416,6 +440,7 @@ IMAGE *
 im_open( const char *filename, const char *mode )
 {
 	IMAGE *im;
+	im_format *format;
 
 	/* Pass in a nonsense name for argv0 ... this init world is only here
 	 * for old programs which are missing an im_init_world() call. We must
@@ -431,107 +456,11 @@ im_open( const char *filename, const char *mode )
 
 	switch( mode[0] ) {
         case 'r':
-{
-		char name[FILENAME_MAX];
-		char options[FILENAME_MAX];
-
-		/* Break any options off the name ... eg. "fred.tif:jpeg,tile" 
-		 * etc.
-		 */
-		im_filename_split( filename, name, options );
-
-		/* Check for other formats.
-
-			FIXME ... should have a table to avoid all this
-			repetition
-
-		 */
-		if( !im_existsf( "%s", name ) ) {
-			im_error( "im_open", 
-				_( "\"%s\" is not readable" ), name );
+		if( !(format = im_format_for_file( filename )) )
 			return( NULL );
-		}
-		else if( im_istiff( name ) ) {
-			/* If TIFF open fails, try going through libmagick.
-			 */
-			if( !(im = open_sub( 
-				im_tiff2vips_header, im_tiff2vips, 
-					filename )) &&
-				!(im = open_sub( 
-					im_magick2vips_header, im_magick2vips, 
-					filename )) )
-				return( NULL );
-		}
-		else if( im_isjpeg( name ) ) {
-			if( !(im = open_sub( 
-				im_jpeg2vips_header, im_jpeg2vips, filename )) )
-				return( NULL );
-		}
-		else if( im_isexr( name ) ) {
-			if( !(im = open_sub( 
-				im_exr2vips_header, im_exr2vips, filename )) )
-				return( NULL );
-		}
-		else if( im_isppm( name ) ) {
-			if( !(im = open_sub( 
-				im_ppm2vips_header, im_ppm2vips, filename )) )
-				return( NULL );
-		}
-		else if( im_ispng( name ) ) {
-			if( !(im = open_sub( 
-				im_png2vips_header, im_png2vips, filename )) )
-				return( NULL );
-		}
-		else if( im_filename_suffix_match( name, im_suffix_csv ) ) {
-			if( !(im = open_sub( 
-				im_csv2vips_header, im_csv2vips, filename )) )
-				return( NULL );
-		}
-		else if( im_isvips( name ) ) {
-			if( mode[1] == 'w' ) {
-				/* Has to be native format for >8 bits.
-				 */
-				if( !(im = im_init( filename )) )
-					return( NULL );
-				if( im_openinrw( im ) ) {
-					im_close( im );
-					return( NULL );
-				}
-				if( im->Bbits != IM_BBITS_BYTE &&
-					im_isMSBfirst( im ) != 
-						im_amiMSBfirst() ) {
-					im_close( im );
-					im_error( "im_open", _( "open for read-"
-						"write for native format "
-						"images only" ) );
-					return( NULL );
-				}
-			}
-			else 
-				im = read_vips( filename );
-		}
-		else if( im_isanalyze( name ) ) {
-			if( !(im = open_sub( 
-				im_analyze2vips_header, im_analyze2vips, 
-					filename )) )
-				return( NULL );
-		}
-		else if( im_ismagick( name ) ) {
-			/* Have this last as it can be very slow to detect
-			 * failure.
-			 */
-			if( !(im = open_sub( 
-				im_magick2vips_header, im_magick2vips, 
-				filename )) )
-				return( NULL );
-		}
-		else {
-			im_error( "im_open", _( "\"%s\" is not "
-				"a supported format" ), filename );
+		if( !(im = open_sub( 
+			format->header, format->load, filename )) )
 			return( NULL );
-		}
-}
-
         	break;
 
 	case 'w':
diff --git a/libsrc/iofuncs/package.c b/libsrc/iofuncs/package.c
index 1d92dec3..28792c63 100644
--- a/libsrc/iofuncs/package.c
+++ b/libsrc/iofuncs/package.c
@@ -72,6 +72,8 @@ extern im_package im__other;
 extern im_package im__relational;
 extern im_package im__video;
 
+extern im_format_package im__format_format;
+
 /* im_guess_prefix() args.
  */
 static im_arg_desc guess_prefix_args[] = {
@@ -419,12 +421,56 @@ static im_package *built_in[] = {
 	&im__video
 };
 
+/* List of loaded formats.
+ */
+static GSList *format_list = NULL;
+
+static gint
+format_compare( im_format *a, im_format *b )
+{
+        return( a->priority - b->priority );
+}
+
+/* Sort the format list after a change.
+ */
+static void
+format_sort( void )
+{
+	format_list = g_slist_sort( format_list, 
+		(GCompareFunc) format_compare );
+}
+
+/* Remove a package of formats.
+ */
+static void
+format_remove( im_format_package *format )
+{
+	int i;
+
+	for( i = 0; i < format->nfuncs; i++ )
+		format_list = g_slist_remove( format_list, format->table[i] );
+	format_sort();
+}
+
+/* Add a package of formats.
+ */
+static void
+format_add( im_format_package *format )
+{
+	int i;
+
+	for( i = 0; i < format->nfuncs; i++ )
+		format_list = g_slist_prepend( format_list, format->table[i] );
+	format_sort();
+}
+
 /* How we represent a loaded plugin.
  */
 typedef struct _Plugin {
 	GModule *module;		/* As loaded by g_module_open() */
 	char *name;			/* Name we loaded */
 	im_package *pack;		/* Package table */
+	im_format_package *format;	/* Package format table */
 } Plugin;
 
 /* List of loaded plugins.
@@ -438,6 +484,8 @@ plugin_free( Plugin *plug )
 {
 	char *name = plug->name ? plug->name : "<unknown>";
 
+	if( plug->format ) 
+		format_remove( plug->format );
 	if( plug->module ) {
 		if( !g_module_close( plug->module ) ) {
 			im_error( "plugin", 
@@ -477,6 +525,7 @@ im_load_plugin( const char *name )
 	plug->module = NULL;
 	plug->name = NULL;
 	plug->pack = NULL;
+	plug->format = NULL;
 	plugin_list = g_slist_prepend( plugin_list, plug );
 
 	/* Attach name.
@@ -511,22 +560,44 @@ im_load_plugin( const char *name )
 		return( NULL );
 	}
 
+	/* The format table is optional.
+	 */
+	if( !g_module_symbol( plug->module, 
+		"format_table", (gpointer *) ((void *) &plug->format) ) ) 
+		plug->format = NULL;
+
 	/* Sanity check.
 	 */
 	if( !plug->pack->name || plug->pack->nfuncs < 0 || 
 		plug->pack->nfuncs > 10000 ) {
 		im_error( "plugin",
-			_( "corrupted package table in plugin \"%s\"" ), 
-				name );
+			_( "corrupted package table in plugin \"%s\"" ), name );
 		plugin_free( plug );
 
 		return( NULL );
 	}
+	if( plug->format ) {
+		if( !plug->format->name || plug->format->nfuncs < 0 || 
+			plug->format->nfuncs > 10000 ) {
+
+			im_error( "plugin",
+				_( "corrupted format table in plugin \"%s\"" ),
+				name );
+			plugin_free( plug );
+
+			return( NULL );
+		}
+	}
 
 #ifdef DEBUG
 	printf( "added package \"%s\" ...\n", plug->pack->name );
 #endif /*DEBUG*/
 
+	/* Add any formats to our format list and sort again.
+	 */
+	if( plug->format ) 
+		format_add( plug->format );
+
 	return( plug->pack );
 }
 
@@ -700,6 +771,89 @@ im_package_of_function( const char *name )
 	return( pack );
 }
 
+/* Map a function over all formats. 
+ */
+void *
+im_map_formats( VSListMap2Fn fn, void *a, void *b )
+{
+	return( im_slist_map2( format_list, fn, a, b ) );
+}
+
+/* Can this format open this file?
+ */
+static void *
+format_for_file_sub( im_format *format, 
+	const char *filename, const char *name )
+{
+	if( format->is_a ) {
+		if( format->is_a( name ) ) 
+			return( format );
+	}
+	else if( im_filename_suffix_match( name, format->suffs ) )
+		return( format );
+
+	return( NULL );
+}
+
+im_format *
+im_format_for_file( const char *filename )
+{
+	char name[FILENAME_MAX];
+	char options[FILENAME_MAX];
+	im_format *format;
+
+	/* Break any options off the name ... eg. "fred.tif:jpeg,tile" 
+	 * etc.
+	 */
+	im_filename_split( filename, name, options );
+
+	if( !im_existsf( "%s", name ) ) {
+		im_error( "im_format_for_file", 
+			_( "\"%s\" is not readable" ), name );
+		return( NULL );
+	}
+
+	format = (im_format *) im_map_formats( 
+		(VSListMap2Fn) format_for_file_sub, 
+		(void *) filename, (void *) name );
+
+	if( !format ) {
+		im_error( "im_format_for_file", 
+			_( "\"%s\" is not in a supported format" ), name );
+		return( NULL );
+	}
+
+	return( format );
+}
+
+/* Can we write this filename with this format?
+ */
+static void *
+format_for_name_sub( im_format *format, 
+	const char *filename, const char *name )
+{
+	if( im_filename_suffix_match( name, format->suffs ) )
+		return( format );
+
+	return( NULL );
+}
+
+im_format *
+im_format_for_name( const char *filename )
+{
+	char name[FILENAME_MAX];
+	char options[FILENAME_MAX];
+
+	/* Break any options off the name ... eg. "fred.tif:jpeg,tile" 
+	 * etc.
+	 */
+	im_filename_split( filename, name, options );
+
+	return( (im_format *) im_map_formats( 
+		(VSListMap2Fn) format_for_name_sub, 
+		(void *) filename, (void *) name ) );
+}
+
 /* Free any store we allocated for the argument list.
  */
 int