Index: trunk/ppSim/src/ppSimLoop.c
===================================================================
--- trunk/ppSim/src/ppSimLoop.c	(revision 26900)
+++ trunk/ppSim/src/ppSimLoop.c	(revision 28125)
@@ -30,4 +30,6 @@
     ppSimType type = ppSimTypeFromString (typeStr); // Type of image to simulate
     int binning = psMetadataLookupS32(NULL, recipe, "BINNING"); // Binning in x and y
+
+    bool psfConvolve = psMetadataLookupBool(NULL, recipe, "PSF.CONVOLVE"); // smooth the image with the PSF?
 
     ppSimUpdateConceptsFPA (fpa, config);
@@ -155,4 +157,11 @@
                 psFree(expCorr);
 
+		// we have two options for generating images which have a PSF:
+		// 1) lay down stars with the PSF model applied : in this case, galaxies do NOT have the PSF
+		// 2) lay down delta functions for stars and smooth the image with a PSF : in this case, the stars land at integer pixel locations
+		if (psfConvolve) {
+		    if (!ppSimSmoothReadout(readout, recipe)) ESCAPE (PS_ERR_UNKNOWN, "problem smoothing image");
+		}
+
             done:
                 if (!ppSimAddNoise(readout->image, readout->variance, cell, config, rng)) ESCAPE (PS_ERR_UNKNOWN, "problem adding noise");