title: Extra pixels at top and bottom of label with image in tkinter
body: <p>In Python 3.2.5 and tkinter, I keep getting 1 or 2 "extra" border-like pixels at the top and bottom of a middle label (of three stacked labels) containing an image (the sides do not have a white border). No matter how I shrink the window or designate no borderwidth, I get a couple of pixels beyond the top and bottom of the label(s).</p>
  
  <p>Here's the code....</p>
  
  <pre><code>        root.withdraw()
  
          LoginErrorMsg = tk.Toplevel()
  
          LoginErrorMsg.title('ERROR! Unauthorized Login Attempt')
  
          # pick .gif file
          # load the file and covert it to a tkinter image object
          imageFile = "ErrorLogin.gif"
          image1 = tk.PhotoImage(file=imageFile)
  
          #set size of Error Message Window
          width = 348
          height = 480
  
          #get size of the whole screen
          xmax = LoginErrorMsg.winfo_screenwidth()
          ymax = LoginErrorMsg.winfo_screenheight()
  
          #calculate centered window coordinates and position it
          x0 = xmax/2 - width/2
          y0 = ymax/2 - height/2
          LoginErrorMsg.geometry("%dx%d+%d+%d" % (width, height, x0, y0))
  
          # make the root window the size of the image
          #root.geometry("%dx%d+%d+%d" % (325, 475, x+100, y+100))
  
          # remove tk icon
          LoginErrorMsg.wm_iconbitmap('Ethicsicon.ico')
  
          #if user closes Error Message Window, clean up memory
          LoginErrorMsg.protocol("WM_DELETE_WINDOW", handler)
  
          # root has no image argument, so use a label as a panel
          panel1 = tk.Label(LoginErrorMsg, text="\nYou have exceeded three (3) login attempts.", background = "white", borderwidth = 0)
          #panel1.configure(background = 'white')
          panel1.pack(side='top', fill='both', expand='yes')
          panel2 = tk.Label(LoginErrorMsg, image=image1, background = "white", borderwidth = 0)
          panel2.pack(side='top', fill='both', expand='yes')
          panel3 = tk.Label(LoginErrorMsg, text="", borderwidth = 0)
          panel3.pack(side='top', fill= 'both', expand='yes')
  
          # save the panel's image from 'garbage collection'
          panel1.image = image1
  
          # put a button on the image panel
          button2 = tk.Button(panel3, text = '  OK  ', command = LeaveSystemCallback)
          button2.pack(side='top')
  
          LoginErrorMsg.update()
  </code></pre>