fix working with closed image file

Author: baskiton

SatsDecoder/systems/image_receiver.py

@@ -31,7 +31,7 @@ def __init__(self, fn, date=0):
         self.open()
 
     def open(self):
-        if not self.f:
+        if not self.f or self.f.closed:
             if self.fn.is_file():
                 mode = 'r+b'
             else:

SatsDecoder/ui.py

@@ -427,6 +427,8 @@ def draw_image(self, i):
             self.canvas.config(scrollregion=self.canvas.bbox(tk.ALL))
 
         if self.active_pil_img:
+            # it is really need?
+            # PIL.Image.close() actually close file object, that used in ImageReceiver
             self.active_pil_img.close()
         self.active_pil_img = i