Index: trunk/psModules/src/camera/pmReadoutStack.c
===================================================================
--- trunk/psModules/src/camera/pmReadoutStack.c	(revision 16680)
+++ trunk/psModules/src/camera/pmReadoutStack.c	(revision 17009)
@@ -96,6 +96,9 @@
         pmReadout *readout = inputs->data[i]; // Readout of interest
 
-        if (!readout || !readout->image) {
-            psError(PS_ERR_UNEXPECTED_NULL, true, "Input readout %ld is NULL or has NULL image.\n", i);
+        if (!readout) {
+            continue;
+        }
+        if (!readout->image) {
+            psError(PS_ERR_UNEXPECTED_NULL, true, "Input readout %ld has NULL image.\n", i);
             return false;
         }