--- libpng-1.6.27.orig/contrib/libtests/pngvalid.c	2016-12-29 01:45:09 +0100
+++ libpng-1.6.27/contrib/libtests/pngvalid.c	2017-01-06 16:01:39 +0100
@@ -7742,13 +7742,11 @@
           * NOTE: this number only affects the internal limit check in pngvalid,
           * it has no effect on the limits applied to the libpng values.
           */
-         that->pm->limit += pow(
 #        if DIGITIZE
-            2.0
+         that->pm->limit += pow( 2.0 /255, data.gamma);
 #        else
-            1.0
+         that->pm->limit += pow( 1.0 /255, data.gamma);
 #        endif
-            /255, data.gamma);
       }
    }