Index: /trunk/ppStack/src/ppStackLoop.c
===================================================================
--- /trunk/ppStack/src/ppStackLoop.c	(revision 21375)
+++ /trunk/ppStack/src/ppStackLoop.c	(revision 21376)
@@ -490,4 +490,5 @@
         pmHDU *hdu = readout->parent->parent->parent->hdu; // HDU for convolved image
         assert(hdu);
+        writeImage(imageNames->data[i], hdu->header, readout->image, config);
         psMetadata *maskHeader = psMetadataCopy(NULL, hdu->header); // Copy of header, for mask
         pmConfigMaskWriteHeader(config, maskHeader);
@@ -630,4 +631,14 @@
     ppStackThreadInit();
     ppStackThreadData *stack = ppStackThreadDataSetup(cells, imageNames, maskNames, varianceNames, config);
+    if (!stack) {
+        psError(PS_ERR_IO, false, "Unable to initialise stack threads.");
+        psFree(subKernels);
+        psFree(subRegions);
+        psFree(inputMask);
+        psFree(matchChi2);
+        psFree(cells);
+        psFree(covariances);
+        return false;
+    }
 
     psTimerStart("PPSTACK_INITIAL");