diff --git a/ChangeLog b/ChangeLog
index ae561cae..7c2e7dbc 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -28,6 +28,7 @@
   accidents on some platforms
 - configure prints a summary of optional packages found at the end
 - im_lhisteq() checks for window too small
+- added invalidate callbacks
 
 25/1/08 started 7.14.0
 - bump all version numbers for new stable
diff --git a/doc/src/pio.tex b/doc/src/pio.tex
index 4db68553..c9906135 100644
--- a/doc/src/pio.tex
+++ b/doc/src/pio.tex
@@ -797,7 +797,8 @@ full details.
 \label{sec:callback}
 
 VIPS lets you attach callbacks to image descriptors. These are functions
-you provide that VIPS will call when certain events occur. 
+you provide that VIPS will call when certain events occur. There are more
+callbacks than are listed here: see the man page for full details.
 
 \subsubsection{Close callbacks}
 
diff --git a/include/vips/proto.h b/include/vips/proto.h
index 9cbb78a2..175bd8cd 100644
--- a/include/vips/proto.h
+++ b/include/vips/proto.h
@@ -157,6 +157,7 @@ int im_add_preclose_callback( IMAGE *, im_callback_fn, void *, void * );
 int im_add_evalstart_callback( IMAGE *, im_callback_fn, void *, void * );
 int im_add_eval_callback( IMAGE *, im_callback_fn, void *, void * );
 int im_add_evalend_callback( IMAGE *, im_callback_fn, void *, void * );
+int im_add_invalidate_callback( IMAGE *, im_callback_fn, void *, void * );
 
 void error_exit( const char *, ... )
 	__attribute__((noreturn, format(printf, 1, 2)));
diff --git a/include/vips/vips.h b/include/vips/vips.h
index 9091f296..630f057d 100644
--- a/include/vips/vips.h
+++ b/include/vips/vips.h
@@ -38,6 +38,8 @@
  * 7/11/07
  * 	- added preclose and evalstart callbacks
  * 	- brought time struct in here
+ * 2/7/08
+ * 	- added invalidate callbacks
  */
 
 /*
@@ -339,6 +341,7 @@ typedef struct im__IMAGE {
 	 */
 	GSList *evalstartfns; 	/* list of start eval callbacks */
 	GSList *preclosefns; 	/* list of pre-close callbacks */
+	GSList *invalidatefns; 	/* list of invalidate callbacks */
 } IMAGE;
 
 /* Only define if IM_ENABLE_DEPRECATED is set.
diff --git a/libsrc/iofuncs/buffer.c b/libsrc/iofuncs/buffer.c
index 7837c61a..31b15d4a 100644
--- a/libsrc/iofuncs/buffer.c
+++ b/libsrc/iofuncs/buffer.c
@@ -563,6 +563,8 @@ im_invalidate_image( IMAGE *im )
 {
 	(void) im_slist_map2( im->regions,
 		(VSListMap2Fn) im_invalidate_region, NULL, NULL );
+	if( im__trigger_callbacks( im->invalidatefns ) )
+		return( im );
 
 	return( NULL );
 }
diff --git a/man/Makefile.am b/man/Makefile.am
index 4bcf7cbb..dc100559 100644
--- a/man/Makefile.am
+++ b/man/Makefile.am
@@ -25,6 +25,7 @@ man_MANS = \
 	im_add_evalstart_callback.3 \
 	im_add_eval_callback.3 \
 	im_add_evalend_callback.3 \
+	im_add_invalidate_callback.3 \
 	im_addgnoise.3 \
 	im_affine.3 \
 	im_allocate_input_array.3 \
diff --git a/man/im_add_invalidate_callback.3 b/man/im_add_invalidate_callback.3
new file mode 100644
index 00000000..0be9c41f
--- /dev/null
+++ b/man/im_add_invalidate_callback.3
@@ -0,0 +1 @@
+.so man3/im_malloc.3
diff --git a/man/im_invalidate.3 b/man/im_invalidate.3
index 487e9587..94cb0156 100644
--- a/man/im_invalidate.3
+++ b/man/im_invalidate.3
@@ -12,5 +12,8 @@ marks all caches related to the image as invalid and requring recalculation.
 It needs to be called if an image changes after being made: for example, after
 a paint action, or perhaps after a new frame has arrived from a video source.
 
+Any invalidate callbacks registered on any of the affected images are
+triggered.
+
 .SH SEE\ ALSO
-im_prepare(3), im_region_buffer(3).
+im_prepare(3), im_region_buffer(3), im_add_invalidate_callback(3).
diff --git a/man/im_malloc.3 b/man/im_malloc.3
index 2f3fb265..e1a9b85b 100644
--- a/man/im_malloc.3
+++ b/man/im_malloc.3
@@ -1,7 +1,8 @@
 .TH IM_AND 3 "30 October 1992"
 .SH NAME
 im_add_close_callback, im_add_eval_callback, im_malloc, im_free,
-im_add_evalend_callback, im_add_evalstart_callback, im_add_preclose_callback \- add image callbacks
+im_add_evalend_callback, im_add_evalstart_callback, im_add_preclose_callback,
+im_add_invalidate_callback \- add image callbacks
 .SH SYNOPSIS
 .B #include <vips/vips.h>
 
@@ -17,6 +18,8 @@ int im_add_eval_callback( IMAGE *, im_callback_fn, void *, void * );
 
 int im_add_evalend_callback( IMAGE *, im_callback_fn, void *, void * );
 
+int im_add_invalidate_callback( IMAGE *, im_callback_fn, void *, void * );
+
 void *im_malloc( IMAGE *, size_t );
 
 int im_free( void * );
@@ -136,6 +139,10 @@ has finished evaluating the image. If you want to output some diagnostics
 from your function (an overflow count, for example), this is the callback to
 use. Again, this can be called many times. 
 
+.B im_add_invalidate_callback(3) 
+adds a callback which will be triggered when VIPS invalidates the cache on an
+image. This is useful for removing images from other, higher-level caches.
+
 .SH RETURN VALUE
 All functions return 0 on success and non-zero on error.
 .SH SEE ALSO