Update app.py

app.py

@@ -127,7 +127,7 @@ def get_slice(filepath, z, c=0):
     if img.ndim==3:
         if (z>=img.shape[0]) | (z<0):
             print('z to big')
-            return np.zeros((img.shape[0], img.shape[1]))
+            return np.zeros((img.shape[1], img.shape[2]))
     if img.ndim==4:
         if (z>=img.shape[0]) | (z<0):
             return np.zeros((img.shape[2], img.shape[3]))