diff -urNad plib-doc.orig/plib-doc-1.8.5/debian/rules plib-doc/plib-doc-1.8.5/debian/rules
--- plib-doc.orig/plib-doc-1.8.5/debian/rules	2015-02-22 11:06:37.863268892 +0000
+++ plib-doc/plib-doc-1.8.5/debian/rules	2015-02-22 11:08:23.839835952 +0000
@@ -16,7 +16,7 @@
 	files=`find $(CURDIR)/debian/libplib-doc/ -name "*.xpm"`;\
 	for file in $$files; do \
 		dir=`dirname $$file`;\
-		convert $$file $$dir/`basename $$file .xpm`.png;\
+		convert $$file +set date:create +set date:modify -define png:exclude-chunk=time $$dir/`basename $$file .xpm`.png;\
 	done
 	find $(CURDIR)/debian/libplib-doc/ -name "*.xpm" | xargs rm -f
 	find $(CURDIR)/debian/libplib-doc/ -name ".svn" -type d | xargs rm -rf