diff --git a/ChangeLog b/ChangeLog
index 70bf3200..6c4b5aa5 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -7,6 +7,7 @@
 - added vips_error_freeze() / vips_error_thaw()
 - used freeze() / thaw() to stop file format sniffers logging spurious errors
 - vipsthumbnail uses embedded jpg thumbnails if it can 
+- rename vips_diag() as vips_info(), add --vips-info flag
 
 3/7/13 started 7.34.2
 - lower priority for Matlab load to reduce segvs from Mat_Open(), thanks
diff --git a/TODO b/TODO
index ab2c95a9..97a646de 100644
--- a/TODO
+++ b/TODO
@@ -1,11 +1,3 @@
-- support webp, see:
-
-	https://github.com/jcupitt/libvips/issues/68
-
-- rename vips_diag() as vips_info(), make it work like a log thing ... 
-  normally no output, can be turned on with a --vips-verbose flag
-
-  handy with vipsthumbnail
 
 - what's the difference between buildlut and invertlut? can we make invertlut
   by just swapping the channels before calling buildlut?
diff --git a/libvips/conversion/sequential.c b/libvips/conversion/sequential.c
index 3f732442..17cd68d7 100644
--- a/libvips/conversion/sequential.c
+++ b/libvips/conversion/sequential.c
@@ -123,7 +123,7 @@ vips_sequential_generate( VipsRegion *or,
 		g_thread_self(), r->top, r->height );
 
 	if( sequential->trace )
-		vips_diag( class->nickname, 
+		vips_info( class->nickname, 
 			"request for line %d, height %d", 
 			r->top, r->height );
 
diff --git a/libvips/include/vips/error.h b/libvips/include/vips/error.h
index 625a17df..6873547f 100644
--- a/libvips/include/vips/error.h
+++ b/libvips/include/vips/error.h
@@ -52,9 +52,9 @@ void vips_error_g( GError **error );
 void vips_warn( const char *domain, const char *fmt, ... )
 	__attribute__((format(printf, 2, 3)));
 void vips_vwarn( const char *domain, const char *fmt, va_list ap );
-void vips_diag( const char *domain, const char *fmt, ... )
+void vips_info( const char *domain, const char *fmt, ... )
 	__attribute__((format(printf, 2, 3)));
-void vips_vdiag( const char *domain, const char *fmt, va_list ap );
+void vips_vinfo( const char *domain, const char *fmt, va_list ap );
 
 void vips_error_exit( const char *fmt, ... )
 	__attribute__((noreturn, format(printf, 1, 2)));
diff --git a/libvips/include/vips/internal.h b/libvips/include/vips/internal.h
index 7ecb9973..c8cd6725 100644
--- a/libvips/include/vips/internal.h
+++ b/libvips/include/vips/internal.h
@@ -83,6 +83,10 @@ extern int vips__progress;
  */
 extern int vips__leak;
 
+/* Show info messages. Handy for debugging. 
+ */
+extern int vips__info;
+
 /* A string giving the image size (in bytes of uncompressed image) above which 
  * we decompress to disc on open. 
  */
diff --git a/libvips/include/vips/vips7compat.h b/libvips/include/vips/vips7compat.h
index 9e406f1c..0135dad6 100644
--- a/libvips/include/vips/vips7compat.h
+++ b/libvips/include/vips/vips7compat.h
@@ -196,8 +196,8 @@ extern "C" {
 #define im_error_clear vips_error_clear
 #define im_warn vips_warn
 #define im_vwarn vips_vwarn
-#define im_diag vips_diag
-#define im_vdiag vips_vdiag
+#define im_diag vips_info
+#define im_vdiag vips_vinfo
 #define error_exit vips_error_exit
 
 #define im_get_argv0 vips_get_argv0
diff --git a/libvips/iofuncs/error.c b/libvips/iofuncs/error.c
index f91de350..48651b58 100644
--- a/libvips/iofuncs/error.c
+++ b/libvips/iofuncs/error.c
@@ -105,6 +105,10 @@
  * supposed to indicate the component which failed.
  */
 
+/* Show info messages. Handy for debugging. 
+ */
+int vips__info = 0;
+
 /* Make global array to keep the error message buffer.
  */
 #define VIPS_MAX_ERROR (10240)
@@ -112,9 +116,6 @@ static char vips_error_text[VIPS_MAX_ERROR] = "";
 static VipsBuf vips_error_buf = VIPS_BUF_STATIC( vips_error_text );
 static int vips_error_freeze_count = 0;
 
-#define IM_DIAGNOSTICS "IM_DIAGNOSTICS"
-#define IM_WARNING "IM_WARNING"
-
 /**
  * vips_error_freeze:
  *
@@ -347,25 +348,26 @@ vips_error_clear( void )
 }
 
 /**
- * vips_vdiag: 
- * @domain: the source of the diagnostic message
+ * vips_vinfo: 
+ * @domain: the source of the message
  * @fmt: printf()-style format string for the message
  * @ap: arguments to the format string
  *
- * Sends a formatted diagnostic message to stderr. If you define the
- * environment variable IM_DIAGNOSTICS, these message are surpressed.
+ * Sends a formatted informational message to stderr if the --vips-info flag
+ * has been given to the program or the environment variable IM_INFO has been
+ * set. 
  *
- * Diagnostic messages are used to report details about the operation of
+ * Informational messages are used to report details about the operation of
  * functions.
  *
- * See also: vips_diag(), vips_warn().
+ * See also: vips_info(), vips_warn().
  */
 void 
-vips_vdiag( const char *domain, const char *fmt, va_list ap )
+vips_vinfo( const char *domain, const char *fmt, va_list ap )
 {
-	if( !g_getenv( IM_DIAGNOSTICS ) ) {
+	if( vips__info ) { 
 		g_mutex_lock( vips__global_lock );
-		(void) fprintf( stderr, _( "%s: " ), _( "vips diagnostic" ) );
+		(void) fprintf( stderr, _( "%s: " ), _( "vips info" ) );
 		if( domain )
 			(void) fprintf( stderr, _( "%s: " ), domain );
 		(void) vfprintf( stderr, fmt, ap );
@@ -375,7 +377,7 @@ vips_vdiag( const char *domain, const char *fmt, va_list ap )
 }
 
 /**
- * vips_diag: 
+ * vips_info: 
  * @domain: the source of the diagnostic message
  * @fmt: printf()-style format string for the message
  * @Varargs: arguments to the format string
@@ -389,12 +391,12 @@ vips_vdiag( const char *domain, const char *fmt, va_list ap )
  * See also: vips_vdiag(), vips_warn().
  */
 void 
-vips_diag( const char *domain, const char *fmt, ... )
+vips_info( const char *domain, const char *fmt, ... )
 {
 	va_list ap;
 
 	va_start( ap, fmt );
-	vips_vdiag( domain, fmt, ap );
+	vips_vinfo( domain, fmt, ap );
 	va_end( ap );
 }
 
@@ -409,12 +411,12 @@ vips_diag( const char *domain, const char *fmt, ... )
  *
  * Warning messages are used to report things like overflow counts.
  *
- * See also: vips_diag(), vips_warn().
+ * See also: vips_info(), vips_warn().
  */
 void 
 vips_vwarn( const char *domain, const char *fmt, va_list ap )
 {	
-	if( !g_getenv( IM_WARNING ) ) {
+	if( !g_getenv( "IM_WARNING" ) ) {
 		g_mutex_lock( vips__global_lock );
 		(void) fprintf( stderr, _( "%s: " ), _( "vips warning" ) );
 		if( domain )
@@ -439,7 +441,7 @@ vips_vwarn( const char *domain, const char *fmt, va_list ap )
  *
  * Warning messages are used to report things like overflow counts.
  *
- * See also: vips_diag(), vips_vwarn().
+ * See also: vips_info(), vips_vwarn().
  */
 void 
 vips_warn( const char *domain, const char *fmt, ... )
diff --git a/libvips/iofuncs/init.c b/libvips/iofuncs/init.c
index 3f157279..f5965f43 100644
--- a/libvips/iofuncs/init.c
+++ b/libvips/iofuncs/init.c
@@ -228,6 +228,11 @@ vips_init( const char *argv0 )
 	bindtextdomain( GETTEXT_PACKAGE, name );
 	bind_textdomain_codeset( GETTEXT_PACKAGE, "UTF-8" );
 
+	/* Default info setting from env.
+	 */
+	if( g_getenv( "IM_INFO" ) ) 
+		vips__info = 1;
+
 	/* Register base vips types.
 	 */
 	(void) vips_image_get_type();
@@ -408,6 +413,9 @@ vips_set_fatal_cb( const gchar *option_name, const gchar *value,
 }
 
 static GOptionEntry option_entries[] = {
+	{ "vips-info", 0, G_OPTION_FLAG_HIDDEN, 
+		G_OPTION_ARG_NONE, &vips__info, 
+		N_( "show informative messages" ), NULL },
 	{ "vips-fatal", 0, G_OPTION_FLAG_HIDDEN | G_OPTION_FLAG_NO_ARG, 
 		G_OPTION_ARG_CALLBACK, (gpointer) &vips_set_fatal_cb, 
 		N_( "abort on first error or warning" ), NULL },