diff --git a/csst_ifs_sim/csst_ifs_sim.py b/csst_ifs_sim/csst_ifs_sim.py
index d3ef00e70a4fdb4bfb63ef2aba7b9242436de8b4..dd51535152c02f824159a3bf28f4637494cd8429 100644
--- a/csst_ifs_sim/csst_ifs_sim.py
+++ b/csst_ifs_sim/csst_ifs_sim.py
@@ -5519,10 +5519,15 @@ class IFSsimulator():
 
         # if self.debug:
         #     exptimes=1
-
-        self.image_b_N = np.zeros((1344, 9672, exptimes))
-
-        self.image_r_N = np.zeros((1856, 13768, exptimes))
+        if exptimes>1:
+            self.image_b_N = np.zeros((1344, 9672, exptimes))
+    
+            self.image_r_N = np.zeros((1856, 13768, exptimes))
+        else:
+            self.image_b_N = np.zeros((1344, 9672))
+    
+            self.image_r_N = np.zeros((1856, 13768))
+            
 
         for idk in range(exptimes):
 
@@ -5590,9 +5595,16 @@ class IFSsimulator():
                 print('Applying cosmetics finished.......')
 
             self.discretise()
+            
+            
+            if exptimes>1:
 
-            self.image_b_N[:, :, idk] = self.image_b[:, :]
-            self.image_r_N[:, :, idk] = self.image_r[:, :]
+                self.image_b_N[:, :, idk] = self.image_b[:, :].copy()
+                self.image_r_N[:, :, idk] = self.image_r[:, :].copy()
+            else:
+                self.image_b_N[:, :] = self.image_b[:, :].copy()
+                self.image_r_N[:, :] = self.image_r[:, :].copy()
+                
 
         self.writeOutputs(simnumber)