diff --git a/ChangeLog b/ChangeLog
index 76eb4d15..4227fac9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -35,6 +35,7 @@
 - redone im_affine*() as a class
 - added input space displacement to affine
 - VipsArea is threadsafe
+- dzsave has a --centre option
 
 31/12/12 started 7.30.7
 - better option parsing for "vips", thanks Haida
diff --git a/libvips/foreign/dzsave.c b/libvips/foreign/dzsave.c
index 8c692789..893bce56 100644
--- a/libvips/foreign/dzsave.c
+++ b/libvips/foreign/dzsave.c
@@ -28,6 +28,8 @@
  * 	- add @background option
  * 1/11/12
  * 	- add @depth option
+ * 21/1/13
+ * 	- add @centre option
  */
 
 /*
@@ -135,8 +137,9 @@ struct _VipsForeignSaveDz {
 	int overlap;
 	int tile_size;
 	VipsForeignDzLayout layout;
-	VipsArea *background;
+	VipsArrayDouble *background;
 	VipsForeignDzDepth depth;
+	gboolean centre;
 
 	Layer *layer;			/* x2 shrink pyr layer */
 
@@ -367,18 +370,39 @@ static int
 write_blank( VipsForeignSaveDz *dz )
 {
 	char buf[PATH_MAX];
-	VipsImage *black;
+	VipsImage *x, *t;
+	int n;
+	VipsArea *ones;
+	double *d;
+	int i;
 
 	vips_snprintf( buf, PATH_MAX, "%s/blank.png", dz->basename );
-	if( vips_black( &black, dz->tile_size, dz->tile_size, 
-		"bands", 3, 
-		NULL ) )
+	if( vips_black( &x, dz->tile_size, dz->tile_size, NULL ) ) 
 		return( -1 );
-	if( vips_image_write_to_file( black, buf ) ) {
-		g_object_unref( black );
+
+	vips_area_get_data( (VipsArea *) dz->background, NULL, &n, NULL, NULL );
+	ones = vips_area_new_array( G_TYPE_DOUBLE, sizeof( double ), n );
+	d = (double *) vips_area_get_data( ones, NULL, NULL, NULL, NULL );
+	for( i = 0; i < n; i++ )
+		d[i] = 1.0; 
+	if( vips_linear( x, &t, 
+		d, 
+		(double *) vips_area_get_data( (VipsArea *) dz->background, 
+			NULL, NULL, NULL, NULL ),
+		n, NULL ) ) {
+		vips_area_unref( ones );
+		g_object_unref( x );
 		return( -1 );
 	}
-	g_object_unref( black );
+	vips_area_unref( ones );
+	g_object_unref( x );
+	x = t;
+
+	if( vips_image_write_to_file( x, buf ) ) {
+		g_object_unref( x );
+		return( -1 );
+	}
+	g_object_unref( x );
 
 	return( 0 );
 }
@@ -708,8 +732,9 @@ strip_work( VipsThreadState *state, void *a )
 	Layer *layer = strip->layer;
 	VipsForeignSaveDz *dz = layer->dz;
 
-	VipsImage *x;
 	char buf[PATH_MAX];
+	VipsImage *x;
+	VipsImage *t;
 
 #ifdef DEBUG
 	printf( "strip_work\n" );
@@ -731,9 +756,7 @@ strip_work( VipsThreadState *state, void *a )
 	/* Google tiles need to be padded up to tilesize.
 	 */
 	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE ) {
-		VipsImage *z;
-
-		if( vips_embed( x, &z, 0, 0, dz->tile_size, dz->tile_size,
+		if( vips_embed( x, &t, 0, 0, dz->tile_size, dz->tile_size,
 			"background", dz->background,
 			NULL ) ) {
 			g_object_unref( x );
@@ -741,7 +764,35 @@ strip_work( VipsThreadState *state, void *a )
 		}
 		g_object_unref( x );
 
-		x = z;
+		x = t;
+	}
+
+	/* If we are centreing we may have a tile which is entirely blank.
+	 * Skip the write in this case, the viewer will use blank.png instead.
+	 */
+	if( dz->centre ) {
+		double *d;
+		int n;
+		double m;
+
+		d = (double *) vips_area_get_data( (VipsArea *) dz->background, 
+			NULL, &n, NULL, NULL );
+		if( vips_equal_const( x, &t, d, n, NULL ) ) {
+			g_object_unref( x );
+			return( -1 );
+		}
+
+		if( vips_min( t, &m, NULL ) ) {
+			g_object_unref( x );
+			g_object_unref( t );
+			return( -1 );
+		}
+		g_object_unref( t );
+
+		if( m == 255 ) {
+			g_object_unref( x );
+			return( 0 );
+		}
 	}
 
 #ifdef DEBUG
@@ -1091,6 +1142,45 @@ vips_foreign_save_dz_build( VipsObject *object )
 		build( object ) )
 		return( -1 );
 
+	/* For centred images, imagine shrinking so that the image fits in a
+	 * single tile, centering in that tile, then expanding back again.
+	 */
+	if( dz->layout == VIPS_FOREIGN_DZ_LAYOUT_GOOGLE &&
+		dz->centre ) {
+		VipsImage *z;
+		Layer *layer;
+		int n_layers;
+		int size;
+
+		if( !(layer = pyramid_build( dz, 
+			NULL, save->ready->Xsize, save->ready->Ysize )) )
+			return( -1 );
+		n_layers = layer->n;
+		/* This would cause interesting problems.
+		 */
+		g_assert( n_layers < 30 );
+		layer_free( layer );
+		size = dz->tile_size * (1 << n_layers);
+
+		if( vips_embed( save->ready, &z, 
+			(size - save->ready->Xsize) / 2, 
+			(size - save->ready->Ysize) / 2, 
+			size, size,
+			"background", dz->background,
+			NULL ) ) 
+			return( -1 );
+
+		VIPS_UNREF( save->ready );
+		save->ready = z;
+
+
+#ifdef DEBUG
+		printf( "centre: centreing within a %d x %d image\n", 
+			size, size );
+#endif
+
+	}
+
 	/* Build the skeleton of the image pyramid.
 	 */
 	if( !(dz->layer = pyramid_build( dz, 
@@ -1219,6 +1309,13 @@ vips_foreign_save_dz_class_init( VipsForeignSaveDzClass *class )
 		VIPS_TYPE_FOREIGN_DZ_DEPTH, 
 			VIPS_FOREIGN_DZ_DEPTH_1PIXEL ); 
 
+	VIPS_ARG_BOOL( class, "centre", 13, 
+		_( "Center" ), 
+		_( "Center image in tile" ),
+		VIPS_ARGUMENT_OPTIONAL_INPUT,
+		G_STRUCT_OFFSET( VipsForeignSaveDz, centre ),
+		FALSE );
+
 	/* How annoying. We stupidly had these in earlier versions.
 	 */
 
@@ -1270,6 +1367,7 @@ vips_foreign_save_dz_init( VipsForeignSaveDz *dz )
  * @tile_size; set tile size 
  * @background: background colour
  * @depth: how deep to make the pyramid
+ * @centre: centre the tiles 
  *
  * Save an image as a set of tiles at various resolutions. By default dzsave
  * uses DeepZoom layout -- use @layout to pick other conventions.
@@ -1286,7 +1384,8 @@ vips_foreign_save_dz_init( VipsForeignSaveDz *dz )
  * 
  * In Google layout mode, edge tiles are expanded to @tile_size by @tile_size 
  * pixels. Normally they are filled with white, but you can set another colour
- * with @background.
+ * with @background. Images are usually placed at the top-left of the tile,
+ * but you can have them centred by turning on @centre. 
  *
  * You can set the size and overlap of tiles with @tile_size and @overlap.
  * They default to the correct settings for the selected @layout. 
diff --git a/po/vips7.pot b/po/vips7.pot
index d02f828e..5b06d578 100644
--- a/po/vips7.pot
+++ b/po/vips7.pot
@@ -7,8 +7,9 @@
 msgid ""
 msgstr ""
 "Project-Id-Version: PACKAGE VERSION\n"
-"Report-Msgid-Bugs-To: \n"
-"POT-Creation-Date: 2013-01-15 14:43+0000\n"
+"Report-Msgid-Bugs-To: http://bugzilla.gnome.org/enter_bug.cgi?"
+"product=glib&keywords=I18N+L10N&component=general\n"
+"POT-Creation-Date: 2013-01-17 13:26+0000\n"
 "PO-Revision-Date: YEAR-MO-DA HO:MI+ZONE\n"
 "Last-Translator: FULL NAME <EMAIL@ADDRESS>\n"
 "Language-Team: LANGUAGE <LL@li.org>\n"
@@ -186,7 +187,7 @@ msgstr ""
 #: ../libvips/conversion/rot.c:359 ../libvips/conversion/replicate.c:196
 #: ../libvips/conversion/tilecache.c:424 ../libvips/conversion/embed.c:550
 #: ../libvips/conversion/cache.c:100 ../libvips/conversion/recomb.c:204
-#: ../libvips/conversion/sequential.c:289 ../libvips/foreign/foreign.c:1357
+#: ../libvips/conversion/sequential.c:303 ../libvips/foreign/foreign.c:1357
 #: ../libvips/resample/resample.c:89
 msgid "Input"
 msgstr ""
@@ -389,7 +390,7 @@ msgstr ""
 #: ../libvips/conversion/extract.c:360 ../libvips/conversion/copy.c:322
 #: ../libvips/conversion/rot.c:360 ../libvips/conversion/replicate.c:197
 #: ../libvips/conversion/tilecache.c:425 ../libvips/conversion/embed.c:551
-#: ../libvips/conversion/cache.c:101 ../libvips/conversion/sequential.c:290
+#: ../libvips/conversion/cache.c:101 ../libvips/conversion/sequential.c:304
 msgid "Input image"
 msgstr ""
 
@@ -643,7 +644,7 @@ msgid "Filename to load output profile from"
 msgstr ""
 
 #: ../libvips/colour/icc_transform.c:723 ../libvips/colour/icc_transform.c:909
-#: ../libvips/colour/scRGB2sRGB.c:191 ../libvips/foreign/dzsave.c:1204
+#: ../libvips/colour/scRGB2sRGB.c:191 ../libvips/foreign/dzsave.c:1215
 msgid "Depth"
 msgstr ""
 
@@ -739,7 +740,7 @@ msgstr ""
 
 #: ../libvips/conversion/flatten.c:382 ../libvips/conversion/join.c:266
 #: ../libvips/conversion/insert.c:393 ../libvips/conversion/embed.c:591
-#: ../libvips/foreign/dzsave.c:1197
+#: ../libvips/foreign/dzsave.c:1208
 msgid "Background"
 msgstr ""
 
@@ -1059,14 +1060,14 @@ msgid "cache an image"
 msgstr ""
 
 #: ../libvips/conversion/tilecache.c:430 ../libvips/conversion/cache.c:113
-#: ../libvips/conversion/sequential.c:302 ../libvips/foreign/tiffsave.c:222
-#: ../libvips/foreign/dzsave.c:1229
+#: ../libvips/conversion/sequential.c:316 ../libvips/foreign/tiffsave.c:222
+#: ../libvips/foreign/dzsave.c:1240
 msgid "Tile height"
 msgstr ""
 
 #: ../libvips/conversion/tilecache.c:431 ../libvips/conversion/cache.c:114
-#: ../libvips/conversion/sequential.c:303 ../libvips/foreign/tiffsave.c:223
-#: ../libvips/foreign/dzsave.c:1230
+#: ../libvips/conversion/sequential.c:317 ../libvips/foreign/tiffsave.c:223
+#: ../libvips/foreign/dzsave.c:1241
 msgid "Tile height in pixels"
 msgstr ""
 
@@ -1091,12 +1092,12 @@ msgid "cache an image as a set of tiles"
 msgstr ""
 
 #: ../libvips/conversion/tilecache.c:732 ../libvips/conversion/cache.c:106
-#: ../libvips/foreign/tiffsave.c:215 ../libvips/foreign/dzsave.c:1222
+#: ../libvips/foreign/tiffsave.c:215 ../libvips/foreign/dzsave.c:1233
 msgid "Tile width"
 msgstr ""
 
 #: ../libvips/conversion/tilecache.c:733 ../libvips/conversion/cache.c:107
-#: ../libvips/foreign/tiffsave.c:216 ../libvips/foreign/dzsave.c:1223
+#: ../libvips/foreign/tiffsave.c:216 ../libvips/foreign/dzsave.c:1234
 msgid "Tile width in pixels"
 msgstr ""
 
@@ -1141,7 +1142,7 @@ msgstr ""
 msgid "How to generate the extra pixels"
 msgstr ""
 
-#: ../libvips/conversion/embed.c:592 ../libvips/foreign/dzsave.c:1198
+#: ../libvips/conversion/embed.c:592 ../libvips/foreign/dzsave.c:1209
 msgid "Colour for background pixels"
 msgstr ""
 
@@ -1197,15 +1198,15 @@ msgstr ""
 msgid "matrix of coefficients"
 msgstr ""
 
-#: ../libvips/conversion/sequential.c:285
+#: ../libvips/conversion/sequential.c:299
 msgid "check sequential access"
 msgstr ""
 
-#: ../libvips/conversion/sequential.c:295
+#: ../libvips/conversion/sequential.c:309
 msgid "trace"
 msgstr ""
 
-#: ../libvips/conversion/sequential.c:296
+#: ../libvips/conversion/sequential.c:310
 msgid "trace pixel requests"
 msgstr ""
 
@@ -1494,55 +1495,55 @@ msgstr ""
 msgid "Directory \"%s\" exists"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1063
+#: ../libvips/foreign/dzsave.c:1074
 msgid "overlap must be less than tile width and height"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1151
+#: ../libvips/foreign/dzsave.c:1162
 msgid "save image to deep zoom format"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1161 ../libvips/foreign/dzsave.c:1215
+#: ../libvips/foreign/dzsave.c:1172 ../libvips/foreign/dzsave.c:1226
 msgid "Base name"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1162 ../libvips/foreign/dzsave.c:1216
+#: ../libvips/foreign/dzsave.c:1173 ../libvips/foreign/dzsave.c:1227
 msgid "Base name to save to"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1168
+#: ../libvips/foreign/dzsave.c:1179
 msgid "Layout"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1169
+#: ../libvips/foreign/dzsave.c:1180
 msgid "Directory layout"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1176
+#: ../libvips/foreign/dzsave.c:1187
 msgid "suffix"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1177
+#: ../libvips/foreign/dzsave.c:1188
 msgid "Filename suffix for tiles"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1183
+#: ../libvips/foreign/dzsave.c:1194
 msgid "Overlap"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1184
+#: ../libvips/foreign/dzsave.c:1195
 msgid "Tile overlap in pixels"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1190
+#: ../libvips/foreign/dzsave.c:1201
 msgid "Tile size"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1191
+#: ../libvips/foreign/dzsave.c:1202
 msgid "Tile size in pixels"
 msgstr ""
 
-#: ../libvips/foreign/dzsave.c:1205
+#: ../libvips/foreign/dzsave.c:1216
 msgid "Pyramid depth"
 msgstr ""
 
@@ -2818,13 +2819,13 @@ msgstr ""
 msgid "TB"
 msgstr ""
 
-#: ../libvips/iofuncs/base64.c:170
+#: ../libvips/iofuncs/base64.c:168
 msgid "too little data"
 msgstr ""
 
 #. We shouldn't really be used for large amounts of data.
 #.
-#: ../libvips/iofuncs/base64.c:176 ../libvips/iofuncs/base64.c:241
+#: ../libvips/iofuncs/base64.c:174 ../libvips/iofuncs/base64.c:239
 msgid "too much data"
 msgstr ""
 
@@ -3029,16 +3030,16 @@ msgstr ""
 msgid "extra tokens after ')'"
 msgstr ""
 
-#: ../libvips/iofuncs/threadpool.c:197
+#: ../libvips/iofuncs/threadpool.c:178
 msgid "unable to create thread"
 msgstr ""
 
-#: ../libvips/iofuncs/threadpool.c:330
+#: ../libvips/iofuncs/threadpool.c:311
 #, c-format
 msgid "threads clipped to %d"
 msgstr ""
 
-#: ../libvips/iofuncs/threadpool.c:394
+#: ../libvips/iofuncs/threadpool.c:375
 msgid "per-thread state for vipsthreadpool"
 msgstr ""
 
@@ -3665,7 +3666,7 @@ msgstr ""
 msgid "B-Splines with antialiasing smoothing"
 msgstr ""
 
-#: ../libvips/resample/nohalo.cpp:1576
+#: ../libvips/resample/nohalo.cpp:1580
 msgid "Edge sharpening resampler with halo reduction"
 msgstr ""