Index: trunk/psModules/src/imcombine/pmSubtraction.c
===================================================================
--- trunk/psModules/src/imcombine/pmSubtraction.c	(revision 30738)
+++ trunk/psModules/src/imcombine/pmSubtraction.c	(revision 32695)
@@ -1487,4 +1487,5 @@
             }
         }
+	psFree(out1->covariance);
         out1->covariance = psImageCovarianceAverage(covars);
         psFree(covars);
@@ -1527,4 +1528,5 @@
             }
         }
+	psFree(out2->covariance);
         out2->covariance = psImageCovarianceAverage(covars);
         psFree(covars);