diff --git a/ChangeLog b/ChangeLog
index 49803c0d..baf146ab 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -57,7 +57,8 @@
 - updated German translation (thanks Chris)
 - fixed typo in im_conv() overflow estimation which could cause errors
 - vips.c has new action syntax, knows about vips8 operations
-- add now has sizealike, retrofitted to old vips7 arith as well
+- add now has sizealike
+- vips7 binops all do sizealike too, also gbandjoin and ifthenelse
 
 30/11/10 started 7.24.0
 - bump for new stable
diff --git a/TODO b/TODO
index 04fcd198..cc53f1b9 100644
--- a/TODO
+++ b/TODO
@@ -1,5 +1,3 @@
-- old arith now does sizealike, add to bool etc. as well
-
 
 - vips_object_set_argument_from_string() leaks output images, because it has
   to, does this matter?
@@ -21,6 +19,8 @@
 
 - make something for Python as well
 
+  use ctypes and not swig so we get an easy Win version
+
   wrap new API for C++
 
 
diff --git a/libvips/arithmetic/add.c b/libvips/arithmetic/add.c
index 45cb8ea2..f628f957 100644
--- a/libvips/arithmetic/add.c
+++ b/libvips/arithmetic/add.c
@@ -93,7 +93,9 @@
  * @out: output image
  *
  * This operation calculates @in1 + @in2 and writes the result to @out. 
- * The images must be the same size. They may have any format. 
+ *
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
  *
  * If the number of bands differs, one of the images 
  * must have one band. In this case, an n-band image is formed from the 
diff --git a/libvips/arithmetic/im_divide.c b/libvips/arithmetic/im_divide.c
index b483f42c..d4df96b0 100644
--- a/libvips/arithmetic/im_divide.c
+++ b/libvips/arithmetic/im_divide.c
@@ -187,8 +187,11 @@ static int bandfmt_divide[10] = {
  * @in2: input #IMAGE 2
  * @out: output #IMAGE
  *
- * This operation calculates @in1 / @in2 and writes the result to @out. 
- * The images must be the same size. They may have any format. 
+ * This operation calculates @in1 / @in2 and writes the result to @out. If any
+ * pixels in @in2 are zero, the corresponding pixel in @out is also zero.
+ *
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
  *
  * If the number of bands differs, one of the images 
  * must have one band. In this case, an n-band image is formed from the 
diff --git a/libvips/arithmetic/im_multiply.c b/libvips/arithmetic/im_multiply.c
index 248ef135..5fe0631c 100644
--- a/libvips/arithmetic/im_multiply.c
+++ b/libvips/arithmetic/im_multiply.c
@@ -158,7 +158,9 @@ static int bandfmt_multiply[10] = {
  * @out: output #IMAGE
  *
  * This operation calculates @in1 * @in2 and writes the result to @out. 
- * The images must be the same size. They may have any format. 
+ *
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
  *
  * If the number of bands differs, one of the images 
  * must have one band. In this case, an n-band image is formed from the 
diff --git a/libvips/arithmetic/im_remainder.c b/libvips/arithmetic/im_remainder.c
index 144eb988..531d2d74 100644
--- a/libvips/arithmetic/im_remainder.c
+++ b/libvips/arithmetic/im_remainder.c
@@ -141,10 +141,13 @@ static int bandfmt_remainder[10] = {
  * @out: output #IMAGE
  *
  * This operation calculates @in1 % @in2 (remainder after division) and writes 
- * the result to @out. The images must be the same size. They may have any 
+ * the result to @out. The images may have any 
  * non-complex format. For float formats, im_remainder() calculates @in1 -
  * @in2 * floor (@in1 / @in2).
  *
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
+ *
  * If the number of bands differs, one of the images 
  * must have one band. In this case, an n-band image is formed from the 
  * one-band image by joining n copies of the one-band image together, and then
diff --git a/libvips/arithmetic/im_subtract.c b/libvips/arithmetic/im_subtract.c
index 3a8c0f8a..09f09be8 100644
--- a/libvips/arithmetic/im_subtract.c
+++ b/libvips/arithmetic/im_subtract.c
@@ -155,7 +155,9 @@ static int bandfmt_subtract[10] = {
  * @out: output image
  *
  * This operation calculates @in1 - @in2 and writes the result to @out. 
- * The images must be the same size. They may have any format. 
+ *
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
  *
  * If the number of bands differs, one of the images 
  * must have one band. In this case, an n-band image is formed from the 
diff --git a/libvips/boolean/bool_dispatch.c b/libvips/boolean/bool_dispatch.c
index f567710b..5af60cab 100644
--- a/libvips/boolean/bool_dispatch.c
+++ b/libvips/boolean/bool_dispatch.c
@@ -54,7 +54,7 @@
  * They are useful for combining the results of
  * the relational and morphological functions.
  * All will work with 
- * images of any type or any mixture of types of any size and of any number 
+ * images of any type or any mixture of types, of any size and of any number 
  * of bands.
  *
  * For binary operations, if the number of bands differs, one of the images 
@@ -66,11 +66,12 @@
  * im_andimage_vec(), you can mix single-element arrays or single-band images
  * freely.
  *
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
+ *
  * The output type is the same as the input type for integer types. Float and
  * complex types are cast to signed int.
  *
- * For binary operations on pairs of images, the images must match in size.
- *
  * You might think im_andimage() would be called "im_and", but that causes
  * problems when we try and make a C++ binding and drop the "im_" prefix.
  */
diff --git a/libvips/boolean/boolean.c b/libvips/boolean/boolean.c
index 466ef359..9442ad12 100644
--- a/libvips/boolean/boolean.c
+++ b/libvips/boolean/boolean.c
@@ -144,8 +144,8 @@ BINARY_BUFFER( AND, & )
  * @out: output #IMAGE
  *
  * This operation calculates @in1 & @in2 and writes the result to @out. 
- * The images must be the same size. They may have any format. They may differ
- * in their number of bands, see above.
+ * The images may have any format. They may differ
+ * in their number of bands, see above. They may differ in size, see above.
  *
  * See also: im_orimage().
  *
@@ -169,8 +169,8 @@ BINARY_BUFFER( OR, | )
  * @out: output #IMAGE
  *
  * This operation calculates @in1 | @in2 and writes the result to @out. 
- * The images must be the same size. They may have any format. They may differ
- * in their number of bands, see above.
+ * The images may have any format. They may differ
+ * in their number of bands, see above. They may differ in size, see above.
  *
  * See also: im_eorimage().
  *
@@ -194,8 +194,8 @@ BINARY_BUFFER( EOR, ^ )
  * @out: output #IMAGE
  *
  * This operation calculates @in1 ^ @in2 and writes the result to @out. 
- * The images must be the same size. They may have any format. They may differ
- * in their number of bands, see above.
+ * The images may have any format. They may differ
+ * in their number of bands, see above. They may differ in size, see above.
  *
  * See also: im_eorimage_vec(), im_andimage().
  *
diff --git a/libvips/conversion/im_gbandjoin.c b/libvips/conversion/im_gbandjoin.c
index 1fca2e8f..0de80b09 100644
--- a/libvips/conversion/im_gbandjoin.c
+++ b/libvips/conversion/im_gbandjoin.c
@@ -20,6 +20,8 @@
  * 	- works for RAD coding too
  * 27/1/10
  * 	- formatalike inputs
+ * 17/5/11
+ * 	- sizealike inputs
  */
 
 /*
@@ -67,6 +69,7 @@
  */
 typedef struct joins {
 	int n;			/* Number of input images */
+	IMAGE **t;		/* Array of temp images */
 	IMAGE **in;		/* Array of input images, NULL-terminated */
 	int *is;		/* An int for SIZEOF_PEL() for each image */
 } Join;
@@ -82,14 +85,17 @@ join_new( IMAGE *out, IMAGE **in, int n )
 	if( !(join = IM_NEW( out, Join )) )
 		return( NULL );
 	join->n = n;
-	if( !(join->in = IM_ARRAY( out, n + 1, IMAGE * )) || 
+	if( !(join->t = IM_ARRAY( out, n, IMAGE * )) || 
+		!(join->in = IM_ARRAY( out, n + 1, IMAGE * )) || 
 		!(join->is = IM_ARRAY( out, n, int )) ) 
 		return( NULL );
 
 	/* Cast inputs up to a common format.
 	 */
-	if( im_open_local_array( out, join->in, n, "im_gbandjoin", "p" ) ||
-		im__formatalike_vec( in, join->in, n ) )
+	if( im_open_local_array( out, join->t, n, "im_gbandjoin", "p" ) ||
+		im_open_local_array( out, join->in, n, "im_gbandjoin", "p" ) ||
+		im__formatalike_vec( in, join->t, n ) ||
+		im__sizealike_vec( join->t, join->in, n ) )
 		return( NULL );
 
 	for( i = 0; i < n; i++ ) 
@@ -166,7 +172,9 @@ join_bands( REGION *or, void *seq, void *a, void *b )
  * bands, with the first n coming from the first image and the last m
  * from the second. 
  *
- * The images must be the same size. 
+ * If the images differ in size, the smaller images are enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
+ *
  * The input images are cast up to the smallest common type (see table 
  * Smallest common format in 
  * <link linkend="VIPS-arithmetic">arithmetic</link>).
@@ -197,7 +205,6 @@ im_gbandjoin( IMAGE **in, IMAGE *out, int n )
 		return( -1 );
 	for( i = 0; i < n; i++ ) 
 		if( im_pincheck( in[i] ) ||
-			im_check_size_same( "im_gbandjoin", in[i], in[0] ) ||
 			im_check_coding_same( "im_gbandjoin", in[i], in[0] ) )
 			return( -1 );
 
@@ -235,7 +242,9 @@ im_gbandjoin( IMAGE **in, IMAGE *out, int n )
  * bands, with the first n coming from the first image and the last m
  * from the second. 
  *
- * The images must be the same size. 
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
+ *
  * The two input images are cast up to the smallest common type (see table 
  * Smallest common format in 
  * <link linkend="VIPS-arithmetic">arithmetic</link>).
diff --git a/libvips/include/vips/internal.h b/libvips/include/vips/internal.h
index efdabbdb..aef1573c 100644
--- a/libvips/include/vips/internal.h
+++ b/libvips/include/vips/internal.h
@@ -137,6 +137,10 @@ int im__bandalike( const char *domain,
 	VipsImage *in1, VipsImage *in2, VipsImage *out1, VipsImage *out2 );
 int im__formatalike_vec( VipsImage **in, VipsImage **out, int n );
 int im__formatalike( VipsImage *in1, VipsImage *in2, VipsImage *out1, VipsImage *out2 );
+int im__sizealike_vec( VipsImage **in, VipsImage **out, int n );
+int im__sizealike( VipsImage *in1, VipsImage *in2, 
+	VipsImage *out1, VipsImage *out2 );
+
 int im__arith_binary( const char *domain, 
 	VipsImage *in1, VipsImage *in2, VipsImage *out, 
 	int format_table[10], 
diff --git a/libvips/relational/im_ifthenelse.c b/libvips/relational/im_ifthenelse.c
index d03e72ca..8ab1fa9c 100644
--- a/libvips/relational/im_ifthenelse.c
+++ b/libvips/relational/im_ifthenelse.c
@@ -18,6 +18,8 @@
  * 25/6/10
  * 	- let the conditional image be any format by adding a (!=0) if
  * 	  necessary
+ * 17/5/11
+ * 	- added sizealike
  */
 
 /*
@@ -198,7 +200,8 @@ ifthenelse( IMAGE *c, IMAGE *a, IMAGE *b, IMAGE *out )
  *
  * Images @a and @b are cast up to the smallest common format.
  *
- * Images @a and @b must match exactly in size.
+ * If the images differ in size, the smaller image is enlarged to match the
+ * larger by adding zero pixels along the bottom and right.
  *
  * See also: im_blend(), im_equal().
  *
@@ -207,9 +210,9 @@ ifthenelse( IMAGE *c, IMAGE *a, IMAGE *b, IMAGE *out )
 int
 im_ifthenelse( IMAGE *c, IMAGE *a, IMAGE *b, IMAGE *out )
 {
-	IMAGE *t[7];
+	IMAGE *t[9];
 
-	if( im_open_local_array( out, t, 7, "im_ifthenelse", "p" ) )
+	if( im_open_local_array( out, t, 9, "im_ifthenelse", "p" ) )
 		return( -1 );
 
 	/* Make a and b match in bands and format. Don't make c match: we
@@ -219,16 +222,23 @@ im_ifthenelse( IMAGE *c, IMAGE *a, IMAGE *b, IMAGE *out )
 		im__bandalike( "im_ifthenelse", t[0], t[1], t[2], t[3] ) )
 		return( -1 );
 
+	/* All 3 must match in size.
+	 */
+	t[4] = c;
+	if( im__sizealike_vec( t + 2, t + 5, 3 ) )
+		return( -1 );
+	c = t[5];
+
 	/* If c is not uchar, do (!=0) to make a uchar image.
 	 */
 	if( c->BandFmt != IM_BANDFMT_UCHAR ) {
-		if( im_notequalconst( c, t[4], 0 ) )
+		if( im_notequalconst( c, t[8], 0 ) )
 			return( -1 );
 
-		c = t[4];
+		c = t[8];
 	}
 
-	if( ifthenelse( c, t[2], t[3], out ) )
+	if( ifthenelse( c, t[6], t[7], out ) )
 		return( -1 );
 
 	return( 0 );