Index: /trunk/psLib/src/math/psRegion.c
===================================================================
--- /trunk/psLib/src/math/psRegion.c	(revision 7495)
+++ /trunk/psLib/src/math/psRegion.c	(revision 7496)
@@ -51,5 +51,17 @@
     }
 
-    if (col0 > col1 || row0 > row1) {
+    // [0:0,0:0] is complete image region
+    if ((col0 == 0) && (col1 == 0) && (row0 == 0) && (row1 == 0)) {
+        return psRegionSet(0,0,0,0);
+    }
+
+    if ((col1 > 0) && (col0 > col1)) {
+        psError(PS_ERR_BAD_PARAMETER_VALUE, true,
+                PS_ERRORTEXT_psImage_SUBSET_RANGE_MALFORMED,
+                col0,col1,row0,row1);
+        return psRegionSet(NAN,NAN,NAN,NAN);
+    }
+
+    if ((row1 > 0) && (row0 > row1)) {
         psError(PS_ERR_BAD_PARAMETER_VALUE, true,
                 PS_ERRORTEXT_psImage_SUBSET_RANGE_MALFORMED,