diff --git a/ChangeLog b/ChangeLog
index 1a318b9d0e..621710e1bf 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -18,6 +18,7 @@ master
 - threadpools size dynamically with load
 - operations can hint threadpool size
 - support for N-colour ICC profiles
+- add vips_palette() to compute a palette for an RGBA image
 
 11/10/22 started 8.13.3
 - improve rules for 16-bit heifsave [johntrunc]
diff --git a/libvips/conversion/conversion.c b/libvips/conversion/conversion.c
index 5886b617d1..a6369ebca4 100644
--- a/libvips/conversion/conversion.c
+++ b/libvips/conversion/conversion.c
@@ -359,101 +359,105 @@ vips_conversion_init( VipsConversion *conversion )
 void
 vips_conversion_operation_init( void )
 {
-	extern GType vips_copy_get_type( void ); 
-	extern GType vips_tile_cache_get_type( void ); 
-	extern GType vips_line_cache_get_type( void ); 
-	extern GType vips_sequential_get_type( void ); 
+	extern GType vips_arrayjoin_get_type( void ); 
+	extern GType vips_autorot_get_type( void ); 
+	extern GType vips_bandbool_get_type( void ); 
+	extern GType vips_bandfold_get_type( void ); 
+	extern GType vips_bandjoin_const_get_type( void ); 
+	extern GType vips_bandjoin_get_type( void ); 
+	extern GType vips_bandmean_get_type( void ); 
+	extern GType vips_bandrank_get_type( void ); 
+	extern GType vips_bandunfold_get_type( void ); 
+	extern GType vips_black_get_type( void ); 
+	extern GType vips_byteswap_get_type( void ); 
 	extern GType vips_cache_get_type( void ); 
+	extern GType vips_cast_get_type( void ); 
+	extern GType vips_composite2_get_type( void ); 
+	extern GType vips_composite_get_type( void ); 
+	extern GType vips_copy_get_type( void ); 
+	extern GType vips_crop_get_type( void ); 
+	extern GType vips_dither_get_type( void ); 
 	extern GType vips_embed_get_type( void ); 
-	extern GType vips_gravity_get_type( void ); 
+	extern GType vips_extract_area_get_type( void ); 
+	extern GType vips_extract_band_get_type( void ); 
+	extern GType vips_falsecolour_get_type( void ); 
+	extern GType vips_flatten_get_type( void ); 
 	extern GType vips_flip_get_type( void ); 
+	extern GType vips_gamma_get_type( void ); 
+	extern GType vips_gaussnoise_get_type( void ); 
+	extern GType vips_gravity_get_type( void ); 
+	extern GType vips_grid_get_type( void ); 
+	extern GType vips_ifthenelse_get_type( void ); 
 	extern GType vips_insert_get_type( void ); 
 	extern GType vips_join_get_type( void ); 
-	extern GType vips_arrayjoin_get_type( void ); 
-	extern GType vips_extract_area_get_type( void ); 
-	extern GType vips_crop_get_type( void ); 
-	extern GType vips_smartcrop_get_type( void ); 
-	extern GType vips_extract_band_get_type( void ); 
+	extern GType vips_line_cache_get_type( void ); 
+	extern GType vips_msb_get_type( void ); 
+	extern GType vips_palette_get_type( void ); 
+	extern GType vips_premultiply_get_type( void ); 
+	extern GType vips_recomb_get_type( void ); 
 	extern GType vips_replicate_get_type( void ); 
-	extern GType vips_cast_get_type( void ); 
-	extern GType vips_bandjoin_get_type( void ); 
-	extern GType vips_bandjoin_const_get_type( void ); 
-	extern GType vips_bandrank_get_type( void ); 
-	extern GType vips_black_get_type( void ); 
-	extern GType vips_rot_get_type( void ); 
 	extern GType vips_rot45_get_type( void ); 
-	extern GType vips_autorot_get_type( void ); 
-	extern GType vips_ifthenelse_get_type( void ); 
+	extern GType vips_rot_get_type( void ); 
+	extern GType vips_scale_get_type( void ); 
+	extern GType vips_sequential_get_type( void ); 
+	extern GType vips_smartcrop_get_type( void ); 
+	extern GType vips_subsample_get_type( void ); 
 	extern GType vips_switch_get_type( void ); 
-	extern GType vips_recomb_get_type( void ); 
-	extern GType vips_bandmean_get_type( void ); 
-	extern GType vips_bandfold_get_type( void ); 
-	extern GType vips_bandunfold_get_type( void ); 
-	extern GType vips_flatten_get_type( void ); 
-	extern GType vips_premultiply_get_type( void ); 
-	extern GType vips_unpremultiply_get_type( void ); 
-	extern GType vips_bandbool_get_type( void ); 
-	extern GType vips_gaussnoise_get_type( void ); 
-	extern GType vips_grid_get_type( void ); 
+	extern GType vips_tile_cache_get_type( void ); 
 	extern GType vips_transpose3d_get_type( void ); 
-	extern GType vips_scale_get_type( void ); 
+	extern GType vips_unpremultiply_get_type( void ); 
 	extern GType vips_wrap_get_type( void ); 
-	extern GType vips_zoom_get_type( void ); 
-	extern GType vips_subsample_get_type( void ); 
-	extern GType vips_msb_get_type( void ); 
-	extern GType vips_byteswap_get_type( void ); 
 	extern GType vips_xyz_get_type( void ); 
-	extern GType vips_falsecolour_get_type( void ); 
-	extern GType vips_gamma_get_type( void ); 
-	extern GType vips_composite_get_type( void ); 
-	extern GType vips_composite2_get_type( void ); 
+	extern GType vips_zoom_get_type( void ); 
 
-	vips_copy_get_type();
-	vips_tile_cache_get_type(); 
-	vips_line_cache_get_type(); 
-	vips_sequential_get_type(); 
+	vips_arrayjoin_get_type();
+	vips_autorot_get_type();
+	vips_bandbool_get_type(); 
+	vips_bandfold_get_type(); 
+	vips_bandjoin_const_get_type();
+	vips_bandjoin_get_type();
+	vips_bandmean_get_type(); 
+	vips_bandrank_get_type();
+	vips_bandunfold_get_type(); 
+	vips_black_get_type();
+	vips_byteswap_get_type(); 
 	vips_cache_get_type(); 
+	vips_cast_get_type();
+	vips_composite2_get_type(); 
+	vips_composite_get_type(); 
+	vips_copy_get_type();
+	vips_crop_get_type();
+	vips_dither_get_type();
 	vips_embed_get_type();
-	vips_gravity_get_type();
+	vips_extract_area_get_type();
+	vips_extract_band_get_type();
+	vips_falsecolour_get_type(); 
+	vips_flatten_get_type(); 
 	vips_flip_get_type();
+	vips_gamma_get_type(); 
+	vips_gaussnoise_get_type(); 
+	vips_gravity_get_type();
+	vips_grid_get_type(); 
+	vips_ifthenelse_get_type();
 	vips_insert_get_type();
 	vips_join_get_type();
-	vips_arrayjoin_get_type();
-	vips_extract_area_get_type();
-	vips_crop_get_type();
-	vips_smartcrop_get_type();
-	vips_extract_band_get_type();
+	vips_line_cache_get_type(); 
+	vips_msb_get_type(); 
+	vips_palette_get_type(); 
+	vips_premultiply_get_type(); 
+	vips_recomb_get_type(); 
 	vips_replicate_get_type();
-	vips_cast_get_type();
-	vips_bandjoin_get_type();
-	vips_bandjoin_const_get_type();
-	vips_bandrank_get_type();
-	vips_black_get_type();
-	vips_rot_get_type();
 	vips_rot45_get_type();
-	vips_autorot_get_type();
-	vips_ifthenelse_get_type();
+	vips_rot_get_type();
+	vips_scale_get_type(); 
+	vips_sequential_get_type(); 
+	vips_smartcrop_get_type();
+	vips_subsample_get_type(); 
 	vips_switch_get_type(); 
-	vips_recomb_get_type(); 
-	vips_bandmean_get_type(); 
-	vips_bandfold_get_type(); 
-	vips_bandunfold_get_type(); 
-	vips_flatten_get_type(); 
-	vips_premultiply_get_type(); 
-	vips_unpremultiply_get_type(); 
-	vips_bandbool_get_type(); 
-	vips_gaussnoise_get_type(); 
-	vips_grid_get_type(); 
+	vips_tile_cache_get_type(); 
 	vips_transpose3d_get_type(); 
-	vips_scale_get_type(); 
+	vips_unpremultiply_get_type(); 
 	vips_wrap_get_type(); 
-	vips_zoom_get_type(); 
-	vips_subsample_get_type(); 
-	vips_msb_get_type(); 
-	vips_byteswap_get_type(); 
 	vips_xyz_get_type(); 
-	vips_falsecolour_get_type(); 
-	vips_gamma_get_type(); 
-	vips_composite_get_type(); 
-	vips_composite2_get_type(); 
+	vips_zoom_get_type(); 
 }
diff --git a/libvips/conversion/dither.c b/libvips/conversion/dither.c
new file mode 100644
index 0000000000..750575cf90
--- /dev/null
+++ b/libvips/conversion/dither.c
@@ -0,0 +1,288 @@
+/* find a dither
+ *
+ * 25/9/22
+ *	- from cgifsave.c
+ */
+
+/*
+
+    This file is part of VIPS.
+    
+    VIPS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <glib/gi18n-lib.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <vips/vips.h>
+#include <vips/internal.h>
+
+#include "pconversion.h"
+#include "../foreign/quantise.h"
+
+typedef struct _VipsDither {
+	VipsConversion parent_instance;
+
+	VipsImage *in;
+	VipsImage *palette;
+	double dither;
+
+        VipsQuantiseAttr *attr;
+	VipsQuantiseImage *image;
+        VipsQuantiseResult *result;
+
+} VipsDither;
+
+typedef VipsConversionClass VipsDitherClass;
+
+G_DEFINE_TYPE( VipsDither, vips_dither, VIPS_TYPE_CONVERSION );
+
+static void
+vips_dither_dispose( GObject *gobject )
+{
+	VipsDither *dither = (VipsDither *) gobject;
+
+        VIPS_FREEF( vips__quantise_result_destroy, dither->result );
+	VIPS_FREEF( vips__quantise_image_destroy, dither->image );
+	VIPS_FREEF( vips__quantise_attr_destroy, dither->attr );
+
+	G_OBJECT_CLASS( vips_dither_parent_class )->dispose( gobject );
+}
+
+static int
+vips_dither_to_rgba( VipsDither *dither, VipsImage *in, VipsImage **out )
+{
+        VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( dither );
+	VipsImage **t = (VipsImage **) 
+		vips_object_local_array( VIPS_OBJECT( dither ), 1 );
+
+	VipsImage *rgba;
+
+	rgba = in;
+
+        if( vips_check_uncoded( class->nickname, rgba ) ||
+                vips_check_format( class->nickname, rgba, VIPS_FORMAT_UCHAR ) ||
+                vips_check_bands_atleast( class->nickname, rgba, 3 ) )
+		return( -1 );
+
+	if( rgba->Bands == 3 ) {
+		if( vips_addalpha( rgba, &t[0], NULL ) ) 
+			return( -1 );
+		rgba = t[0];
+	}
+	else if( rgba->Bands > 4 ) {
+		if( vips_extract_band( rgba, &t[0], 0, "n", 4, NULL ) )
+			return( -1 );
+		rgba = t[0];
+	}
+
+	g_object_ref( rgba );
+	*out = rgba;
+
+	return( 0 );
+}
+
+static int
+vips_dither_build( VipsObject *object )
+{
+        VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
+	VipsConversion *conversion = VIPS_CONVERSION( object );
+	VipsDither *dither = (VipsDither *) object;
+	VipsImage **t = (VipsImage **) vips_object_local_array( object, 5 );
+
+	VipsImage *in;
+	VipsImage *palette;
+	guint32 fake_image[257];
+	int n_colours;
+
+	if( VIPS_OBJECT_CLASS( vips_dither_parent_class )->build( object ) )
+		return( -1 );
+
+	in = dither->in;
+	palette = dither->palette;
+
+	/* The palette can't have more than 256 entries.
+	 */
+	if( palette->Xsize != 1 && 
+		palette->Ysize != 1 ) {
+		vips_error( class->nickname, "%s", 
+			_( "palettes must have width or height 1" ) );
+		return( -1 );
+	}
+	if( VIPS_IMAGE_N_PELS( palette ) > 256 ) {
+		vips_error( class->nickname, "%s", 
+			_( "palettes must have not have more than "
+				"256 elements" ) );
+		return( -1 );
+	}
+	n_colours = palette->Xsize * palette->Ysize;
+
+        /* We only work for 8-bit RGBA images.
+         */
+	if( vips_dither_to_rgba( dither, in, &t[0] ) ||
+		vips_dither_to_rgba( dither, palette, &t[1] ) )
+		return( -1 );
+	in = t[0];
+	palette = t[1];
+
+	/* We need the whole thing in memory.
+	 */
+	if( vips_image_wio_input( in ) ||
+		vips_image_wio_input( palette ) )
+		return( -1 );
+
+        dither->attr = vips__quantise_attr_create();
+	vips__quantise_set_max_colors( dither->attr, n_colours );
+        vips__quantise_set_quality( dither->attr, 0, 100 );
+
+	/* Make a fake image from the input palette and quantise that to get
+	 * the context we use for dithering.
+	 */
+	memcpy( fake_image, VIPS_IMAGE_ADDR( palette, 0, 0 ), 
+		n_colours * sizeof( int ) );
+	dither->image = vips__quantise_image_create_rgba( dither->attr,
+		fake_image, n_colours, 1, 0.0 );
+	if( vips__quantise_image_quantize_fixed( dither->image, 
+		dither->attr, &dither->result ) ) {
+		vips_error( class->nickname,
+			"%s", _( "quantisation failed" ) );
+		return( -1 );
+	}
+	VIPS_FREEF( vips__quantise_image_destroy, dither->image );
+
+{
+	const VipsQuantisePalette *lp = 
+		vips__quantise_get_palette( dither->result );
+
+	for( int i = 0; i < lp->count; i++ )
+		printf( "%d) r = %d, g = %d, b = %d, a = %d\n",
+			i,
+			lp->entries[i].r,
+			lp->entries[i].g,
+			lp->entries[i].b,
+			lp->entries[i].a );
+}
+
+	/* The frame index buffer.
+	 */
+	vips_image_init_fields( conversion->out,
+		in->Xsize, in->Ysize, 1, 
+		VIPS_FORMAT_UCHAR, 
+		VIPS_CODING_NONE, VIPS_INTERPRETATION_B_W, 1.0, 1.0 );
+	if( vips_image_write_prepare( conversion->out ) ) 
+		return( -1 );
+	dither->image = vips__quantise_image_create_rgba( dither->attr,
+		VIPS_IMAGE_ADDR( in, 0, 0 ), in->Xsize, in->Ysize, 0.0 );
+
+	/* Now dither!
+	 */
+	vips__quantise_set_dithering_level( dither->result, dither->dither );
+	if( vips__quantise_write_remapped_image( dither->result, dither->image, 
+		VIPS_IMAGE_ADDR( conversion->out, 0, 0 ), 
+		VIPS_IMAGE_N_PELS( conversion->out ) ) ) {
+		vips_error( class->nickname, "%s", _( "dither failed" ) );
+		return( -1 );
+	}
+
+	return( 0 );
+}
+
+static void
+vips_dither_class_init( VipsDitherClass *class )
+{
+	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
+	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
+
+	gobject_class->dispose = vips_dither_dispose;
+	gobject_class->set_property = vips_object_set_property;
+	gobject_class->get_property = vips_object_get_property;
+
+	vobject_class->nickname = "dither";
+	vobject_class->description = _( "dither image into palette" );
+	vobject_class->build = vips_dither_build;
+
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
+	VIPS_ARG_IMAGE( class, "in", 0, 
+		_( "Input" ), 
+		_( "Input image" ),
+		VIPS_ARGUMENT_REQUIRED_INPUT,
+		G_STRUCT_OFFSET( VipsDither, in ) );
+
+	VIPS_ARG_IMAGE( class, "palette", 3, 
+		_( "Palette" ), 
+		_( "Palette image" ),
+		VIPS_ARGUMENT_REQUIRED_INPUT,
+		G_STRUCT_OFFSET( VipsDither, palette ) );
+
+	VIPS_ARG_DOUBLE( class, "dither", 10,
+		_( "Dithering" ),
+		_( "Amount of dithering" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsDither, dither ),
+		0.0, 1.0, 1.0 );
+
+}
+
+static void
+vips_dither_init( VipsDither *dither )
+{
+}
+
+/**
+ * vips_dither: (method)
+ * @in: input image 
+ * @out: (out): output image
+ * @palette: (in): palette image
+ * @...: %NULL-terminated list of optional named arguments
+ *
+ * Optional arguments:
+ *
+ * * @dither: %gdouble, dithering level
+ *
+ * Dither @in using @palette. 
+ *
+ * Use @dither to set the degree of Floyd-Steinberg dithering.
+ *
+ * See also: vips_palette().
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int
+vips_dither( VipsImage *in, VipsImage **out, VipsImage *palette, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, palette );
+	result = vips_call_split( "dither", ap, in, out, palette );
+	va_end( ap );
+
+	return( result );
+}
diff --git a/libvips/conversion/meson.build b/libvips/conversion/meson.build
index 361b0711e9..cac8cc534c 100644
--- a/libvips/conversion/meson.build
+++ b/libvips/conversion/meson.build
@@ -1,44 +1,46 @@
 conversion_sources = files(
-    'switch.c',
-    'transpose3d.c',
-    'composite.cpp',
-    'smartcrop.c',
-    'conversion.c',
-    'tilecache.c',
-    'gamma.c',
-    'sequential.c',
-    'flatten.c',
-    'premultiply.c',
-    'unpremultiply.c',
+    'arrayjoin.c',
+    'autorot.c',
+    'bandary.c',
+    'bandbool.c',
+    'bandfold.c',
+    'bandjoin.c',
+    'bandmean.c',
+    'bandrank.c',
+    'bandunfold.c',
     'byteswap.c',
     'cache.c',
+    'cast.c',
+    'composite.cpp',
+    'conversion.c',
     'copy.c',
+    'dither.c',
     'embed.c',
+    'extract.c',
+    'falsecolour.c',
+    'flatten.c',
     'flip.c',
+    'gamma.c',
+    'grid.c',
+    'ifthenelse.c',
     'insert.c',
     'join.c',
-    'arrayjoin.c',
-    'extract.c',
-    'replicate.c',
-    'cast.c',
-    'bandjoin.c',
-    'bandrank.c',
+    'msb.c',
+    'palette.c',
+    'premultiply.c',
     'recomb.c',
-    'bandmean.c',
-    'bandfold.c',
-    'bandunfold.c',
-    'bandbool.c',
-    'bandary.c',
-    'rot.c',
+    'replicate.c',
     'rot45.c',
-    'autorot.c',
-    'ifthenelse.c',
-    'falsecolour.c',
-    'msb.c',
-    'grid.c',
+    'rot.c',
     'scale.c',
-    'wrap.c',
+    'sequential.c',
+    'smartcrop.c',
     'subsample.c',
+    'switch.c',
+    'tilecache.c',
+    'transpose3d.c',
+    'unpremultiply.c',
+    'wrap.c',
     'zoom.c',
 )
 
diff --git a/libvips/conversion/palette.c b/libvips/conversion/palette.c
new file mode 100644
index 0000000000..6cd017d8a0
--- /dev/null
+++ b/libvips/conversion/palette.c
@@ -0,0 +1,241 @@
+/* find a palette
+ *
+ * 25/9/22
+ *	- from cgifsave.c
+ */
+
+/*
+
+    This file is part of VIPS.
+    
+    VIPS is free software; you can redistribute it and/or modify
+    it under the terms of the GNU Lesser General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Lesser General Public License for more details.
+
+    You should have received a copy of the GNU Lesser General Public License
+    along with this program; if not, write to the Free Software
+    Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
+    02110-1301  USA
+
+ */
+
+/*
+
+    These files are distributed with VIPS - http://www.vips.ecs.soton.ac.uk
+
+ */
+
+#ifdef HAVE_CONFIG_H
+#include <config.h>
+#endif /*HAVE_CONFIG_H*/
+#include <glib/gi18n-lib.h>
+
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <vips/vips.h>
+#include <vips/internal.h>
+
+#include "pconversion.h"
+#include "../foreign/quantise.h"
+
+typedef struct _VipsPalette {
+	VipsConversion parent_instance;
+
+	VipsImage *in;
+	int effort;
+	int bitdepth;
+} VipsPalette;
+
+typedef VipsConversionClass VipsPaletteClass;
+
+G_DEFINE_TYPE( VipsPalette, vips_palette, VIPS_TYPE_CONVERSION );
+
+static int
+vips_palette_write( VipsPalette *palette, VipsImage *out, 
+	const VipsQuantisePalette *lp )
+{
+	VipsPel line[256 * 4];
+	VipsPel *rgba;
+
+	g_assert( lp->count <= 256 );
+
+	rgba = line;
+	for( int i = 0; i < lp->count; i++ ) {
+		rgba[0] = lp->entries[i].r;
+		rgba[1] = lp->entries[i].g;
+		rgba[2] = lp->entries[i].b;
+		rgba[3] = lp->entries[i].a;
+
+		rgba += 4;
+	}
+
+	vips_image_init_fields( out,
+		lp->count, 1, 4, VIPS_FORMAT_UCHAR,
+		VIPS_CODING_NONE, VIPS_INTERPRETATION_sRGB, 
+		1.0, 1.0 );
+
+	if( vips_image_write_line( out, 0, line ) )
+		return( -1 ); 
+
+	return( 0 );
+}
+
+static int
+vips_palette_build( VipsObject *object )
+{
+        VipsObjectClass *class = VIPS_OBJECT_GET_CLASS( object );
+	VipsConversion *conversion = VIPS_CONVERSION( object );
+	VipsPalette *palette = (VipsPalette *) object;
+	VipsImage **t = (VipsImage **) vips_object_local_array( object, 5 );
+
+	VipsImage *in;
+        VipsQuantiseResult *result;
+        VipsQuantiseAttr *attr;
+	VipsQuantiseImage *image;
+
+	if( VIPS_OBJECT_CLASS( vips_palette_parent_class )->
+		build( object ) )
+		return( -1 );
+
+        /* We only work for 8-bit RGBA images.
+         */
+	in = palette->in;
+        if( vips_check_uncoded( class->nickname, in ) ||
+                vips_check_format( class->nickname, in, VIPS_FORMAT_UCHAR ) ||
+                vips_check_bands_atleast( class->nickname, in, 3 ) )
+		return( -1 );
+
+	/* To RGBA.
+	 */
+	if( in->Bands == 3 ) {
+		if( vips_addalpha( in, &t[0], NULL ) )
+			return( -1 );
+		in = t[0];
+	}
+	else if( in->Bands > 4 ) {
+		if( vips_extract_band( in, &t[0], 0, "n", 4, NULL ) )
+			return( -1 );
+		in = t[0];
+	}
+
+	/* We need the whole thing in memory.
+	 */
+	if( vips_image_wio_input( in ) )
+		return( -1 );
+
+        attr = vips__quantise_attr_create();
+	vips__quantise_set_max_colors( attr,
+                VIPS_MIN( 255, 1 << palette->bitdepth ) );
+        vips__quantise_set_quality( attr, 0, 100 );
+        vips__quantise_set_speed( attr, 11 - palette->effort );
+
+	image = vips__quantise_image_create_rgba( attr,
+		VIPS_IMAGE_ADDR( in, 0, 0 ), in->Xsize, in->Ysize, 0.0 );
+
+	result = NULL;
+        if( vips__quantise_image_quantize_fixed( image, attr, &result ) ) {
+		VIPS_FREEF( vips__quantise_image_destroy, image );
+		VIPS_FREEF( vips__quantise_attr_destroy, attr );
+                vips_error( class->nickname, "%s", _( "quantisation failed" ) );
+                return( -1 );
+        }
+
+	if( vips_palette_write( palette, conversion->out, 
+		vips__quantise_get_palette( result ) ) ) {
+		VIPS_FREEF( vips__quantise_result_destroy, result );
+		return( -1 );
+	}
+
+	VIPS_FREEF( vips__quantise_image_destroy, image );
+        VIPS_FREEF( vips__quantise_attr_destroy, attr );
+
+        VIPS_FREEF( vips__quantise_result_destroy, result );
+
+	return( 0 );
+}
+
+static void
+vips_palette_class_init( VipsPaletteClass *class )
+{
+	GObjectClass *gobject_class = G_OBJECT_CLASS( class );
+	VipsObjectClass *vobject_class = VIPS_OBJECT_CLASS( class );
+	VipsOperationClass *operation_class = VIPS_OPERATION_CLASS( class );
+
+	gobject_class->set_property = vips_object_set_property;
+	gobject_class->get_property = vips_object_get_property;
+
+	vobject_class->nickname = "palette";
+	vobject_class->description = _( "compute image palette" );
+	vobject_class->build = vips_palette_build;
+
+	operation_class->flags = VIPS_OPERATION_SEQUENTIAL;
+
+	VIPS_ARG_IMAGE( class, "in", 0, 
+		_( "Input" ), 
+		_( "Input image" ),
+		VIPS_ARGUMENT_REQUIRED_INPUT,
+		G_STRUCT_OFFSET( VipsPalette, in ) );
+
+	VIPS_ARG_INT( class, "effort", 11,
+		_( "Effort" ),
+		_( "Quantisation effort" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsPalette, effort ),
+		1, 10, 7 );
+
+	VIPS_ARG_INT( class, "bitdepth", 1,
+		_( "Bit depth" ),
+		_( "Compute an N bit palette" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsPalette, bitdepth ),
+		0, 16, 8 );
+
+}
+
+static void
+vips_palette_init( VipsPalette *palette )
+{
+}
+
+/**
+ * vips_palette: (method)
+ * @in: input image 
+ * @out: (out): output image
+ * @...: %NULL-terminated list of optional named arguments
+ *
+ * Optional arguments:
+ *
+ * * @effort: %gint, how much effort to spend on the search
+ * * @bitdepth: %gint, bitdepth for generated palette
+ *
+ * Find the most common colours in an 8-bit RGB or RGBA image.
+ *
+ * Set @bitdepth to control the size of the computed palette. By default it
+ * finds an 8-bit palette, or 256 colours. 
+ *
+ * Set @effort to control the CPU effort (1 is the fastest,
+ * 10 is the slowest, 7 is the default).
+ *
+ * See also: vips_dither(), vips_maplut().
+ *
+ * Returns: 0 on success, -1 on error
+ */
+int
+vips_palette( VipsImage *in, VipsImage **out, ... )
+{
+	va_list ap;
+	int result;
+
+	va_start( ap, out );
+	result = vips_call_split( "palette", ap, in, out );
+	va_end( ap );
+
+	return( result );
+}
diff --git a/libvips/foreign/cgifsave.c b/libvips/foreign/cgifsave.c
index 1b7fbd838a..b03890d797 100644
--- a/libvips/foreign/cgifsave.c
+++ b/libvips/foreign/cgifsave.c
@@ -484,8 +484,10 @@ vips_foreign_save_cgif_write_frame( VipsForeignSaveCgif *cgif )
 		/* Local mode. Pick the global, this or previous palette.
 		 */
 		if( vips_foreign_save_cgif_pick_quantiser( cgif, 
-			image, &quantisation_result, &use_local ) )
+			image, &quantisation_result, &use_local ) ) {
+			VIPS_FREEF( vips__quantise_image_destroy, image );
 			return( -1 );
+		}
 	}
 
 	lp = vips__quantise_get_palette( quantisation_result );
diff --git a/libvips/include/vips/conversion.h b/libvips/include/vips/conversion.h
index b3dd66aae6..db67572470 100644
--- a/libvips/include/vips/conversion.h
+++ b/libvips/include/vips/conversion.h
@@ -336,6 +336,8 @@ VIPS_API
 int vips_unpremultiply( VipsImage *in, VipsImage **out, ... )
 	G_GNUC_NULL_TERMINATED;
 VIPS_API
+int vips_palette( VipsImage *in, VipsImage **out, ... );
+VIPS_API
 int vips_composite( VipsImage **in, VipsImage **out, int n, int *mode, ... )
 	G_GNUC_NULL_TERMINATED;
 VIPS_API