diff --git a/debian/changelog b/debian/changelog
index 07e3a0df..6951b550 100644
--- a/debian/changelog
+++ b/debian/changelog
@@ -1,3 +1,11 @@
+skimage (0.9.3-4) unstable; urgency=low
+
+  * debian/rules
+    don't optimize pngs in post build processors some derivatives use
+    palette changes break tests and documented examples
+
+ -- Julian Taylor <jtaylor.debian@googlemail.com>  Thu, 23 Jan 2014 20:48:51 +0100
+
 skimage (0.9.3-3) unstable; urgency=low
 
   * debian/control
diff --git a/debian/rules b/debian/rules
index 03a4cff4..3a7bff2b 100755
--- a/debian/rules
+++ b/debian/rules
@@ -4,6 +4,8 @@
 PACKAGE2_NAME = python-skimage
 PACKAGE3_NAME = python3-skimage
 PKG_TMP = $(CURDIR)/debian/tmp
+# don't optimize pngs, palette changes break tests and documented examples
+export NO_PNG_PKG_MANGLE=1
 
 PYVERS = $(shell pyversions -vr)
 PYVER = $(shell pyversions  -vd)