diff --git a/331_fine_tune_SAM_mito.ipynb b/331_fine_tune_SAM_mito.ipynb
index 6c4d70761..9d2ed9d64 100644
--- a/331_fine_tune_SAM_mito.ipynb
+++ b/331_fine_tune_SAM_mito.ipynb
@@ -1064,6 +1064,7 @@
         "large_test_images = tifffile.imread(\"/content/drive/MyDrive/ColabNotebooks/data/mitochondria/small_dataset_for_training/images/12_training_mito_images.tif\")\n",
         "large_test_image = large_test_images[1]\n",
         "patches = patchify(large_test_image, (256, 256), step=256)  #Step=256 for 256 patches means no overlap\n"
+        "patches = np.stack((patches,) * 3, axis=-1)  #expanding dimension \n"
       ],
       "metadata": {
         "id": "VN3AXZpTAW85"
@@ -2312,4 +2313,4 @@
   },
   "nbformat": 4,
   "nbformat_minor": 0
-}
\ No newline at end of file
+}