Index: trunk/psphot/src/psphotAddNoise.c
===================================================================
--- trunk/psphot/src/psphotAddNoise.c	(revision 25383)
+++ trunk/psphot/src/psphotAddNoise.c	(revision 25755)
@@ -50,4 +50,5 @@
 
         // skip sources which were not subtracted
+	// NOTE: this bit is not modified when pmSourceOp applies to noise
         if (!(source->tmpFlags & PM_SOURCE_TMPF_SUBTRACTED)) continue;
 
@@ -79,5 +80,5 @@
         axes.minor *= SIZE;
         newshape = psEllipseAxesToShape (axes);
-        PAR[PM_PAR_I0]  = FACTOR*PS_SQR(oldI0);
+        PAR[PM_PAR_I0]  = FACTOR*oldI0;
         PAR[PM_PAR_SXX] = newshape.sx;
         PAR[PM_PAR_SYY] = newshape.sy;