diff --git a/VideoReceiverSFP/gui/viewer_sar.py b/VideoReceiverSFP/gui/viewer_sar.py
index d3aeebf..d639eed 100644
--- a/VideoReceiverSFP/gui/viewer_sar.py
+++ b/VideoReceiverSFP/gui/viewer_sar.py
@@ -41,11 +41,10 @@ class SfpSarViewer:
         img_frame = ttk.Frame(main)
         img_frame.grid(row=0, column=0, sticky="nsew")
         
-        # Use Canvas to ensure fixed size display
+        # Use Canvas to ensure fixed size display; we'll draw images into it
         self._img_canvas = tk.Canvas(img_frame, width=484, height=484, bg="black", highlightthickness=0)
         self._img_canvas.pack(fill="both", expand=True)
-        self._img_label = tk.Label(self._img_canvas, bg="black")
-        self._img_canvas.create_window(242, 242, window=self._img_label)
+        self._canvas_image_id = None
 
         # Right controls
         ctrl_frame = ttk.Labelframe(main, text="SAR Controls", padding=8)
@@ -278,14 +277,12 @@ class SfpSarViewer:
             except Exception:
                 disp_img = img
 
-            # Resize to fit the label widget while preserving aspect ratio.
+            # Resize to fit the canvas while preserving aspect ratio.
             try:
-                w = self._img_label.winfo_width()
-                h = self._img_label.winfo_height()
-                # If widget not yet laid out, winfo_ reports 1; use geometry fallback
+                w = self._img_canvas.winfo_width()
+                h = self._img_canvas.winfo_height()
                 if w > 2 and h > 2:
                     max_size = (max(1, w), max(1, h))
-                    # Resize the display image copy (disp_img) not the raw image
                     try:
                         disp_img = disp_img.copy()
                         disp_img.thumbnail(max_size, Image.LANCZOS)
@@ -301,27 +298,35 @@ class SfpSarViewer:
             except Exception:
                 pass
 
-            # Save a debug copy
-            try:
-                dumps_dir = os.path.join(os.getcwd(), 'dumps')
-                os.makedirs(dumps_dir, exist_ok=True)
-                debug_path = os.path.join(dumps_dir, 'VideoReceiverSFP_sar_last.png')
-                try:
-                    disp_img.save(debug_path)
-                except Exception:
-                    img.save(debug_path)
-            except Exception:
-                pass
-
             try:
                 return ImageTk.PhotoImage(disp_img, master=self._root)
             except Exception:
-                # Fallback to default behavior
                 return ImageTk.PhotoImage(disp_img)
         except Exception:
             logging.exception("SfpSarViewer: failed to build tk image")
             return None
 
+    def _draw_image_on_canvas(self, photo_image: ImageTk.PhotoImage) -> None:
+        try:
+            # Keep reference to avoid GC
+            self._last_photoimage = photo_image
+            # Draw into canvas, centered
+            if self._canvas_image_id is None:
+                self._canvas_image_id = self._img_canvas.create_image(
+                    self._img_canvas.winfo_width() // 2,
+                    self._img_canvas.winfo_height() // 2,
+                    image=self._last_photoimage,
+                    anchor='center'
+                )
+            else:
+                self._img_canvas.itemconfigure(self._canvas_image_id, image=self._last_photoimage)
+                # Recenter in case canvas size changed
+                self._img_canvas.coords(self._canvas_image_id,
+                                         self._img_canvas.winfo_width() // 2,
+                                         self._img_canvas.winfo_height() // 2)
+        except Exception:
+            pass
+
     def _poll(self):
         try:
             frame = None
@@ -337,7 +342,7 @@ class SfpSarViewer:
                 tkimg = self._build_tk_image(frame)
                 if tkimg is not None:
                     self._photo = tkimg
-                    self._img_label.config(image=self._photo)
+                    self._draw_image_on_canvas(self._photo)
             elif params_changed:
                 # No new frame but params changed: refresh current image
                 self._refresh_current_image()
@@ -384,8 +389,8 @@ class SfpSarViewer:
             except Exception:
                 pil = raw
             try:
-                w = self._img_label.winfo_width()
-                h = self._img_label.winfo_height()
+                w = self._img_canvas.winfo_width()
+                h = self._img_canvas.winfo_height()
                 if w > 2 and h > 2:
                     pil = pil.copy()
                     pil.thumbnail((max(1, w), max(1, h)), Image.LANCZOS)
@@ -398,8 +403,8 @@ class SfpSarViewer:
             with self._lock:
                 self._photo = tkimg
             try:
-                self._img_label.config(image=self._photo)
-                self._img_label.update_idletasks()
+                self._draw_image_on_canvas(self._photo)
+                self._img_canvas.update_idletasks()
             except Exception:
                 pass
         except Exception: