Index: trunk/psphot/src/psphotExtendedSourceAnalysisByObject.c
===================================================================
--- trunk/psphot/src/psphotExtendedSourceAnalysisByObject.c	(revision 29548)
+++ trunk/psphot/src/psphotExtendedSourceAnalysisByObject.c	(revision 29936)
@@ -41,6 +41,5 @@
 
     // number of images used to define sources
-    int nImages = psMetadataLookupS32 (&status, config->arguments, "PSPHOT.INPUT.NUM");
-    psAssert (status, "programming error: must define PSPHOT.INPUT.NUM");
+    int nImages = psphotFileruleCount(config, filerule);
 
     // generate look-up arrays for readouts