title: How to setup a background image on a tk.TopLevel()
body: <p>I'm trying to add a background to a tk.TopLevel() window.</p>
  
  <p>I have succeeded using the same code as follows to add a bakground to a tk.Tk(). However, the same code doesn't work and leaves me with the default background.</p>
  
  <pre class="lang-py prettyprint-override"><code>def add_window_launching():
      #initializing window
      add_window=tk.Toplevel()
      add_window.title("Inventaire Petits Débrouillards")
      add_window.geometry('900x350')
      add_window.resizable(width=False, height=False)
  
      #Setting background
      raw_image=Image.open("C:/Users/Ordinateur/Desktop/db-update-petits-debrouillards/UI/ajout.png")
      background_image=ImageTk.PhotoImage(raw_image)
      background_label = tk.Label(add_window, image=background_image)
  
      #Adding widgets
      welcome_text=tk.Label(add_window, text="Text")
      object_description=tk.Label(add_window, text="Description de l'objet :")
      description_entry=tk.Entry(add_window, width=100)
      row=SQL.Entries([description_entry], add_window)
      submit_button=tk.Button(add_window, text="Ajouter", command=row.adding_entry)
  
      #Organizing window
      background_label.place(x=0, y=0, relwidth=1, relheight=1)
      welcome_text.place(anchor="n", relx=0.5, rely=0.25)
      object_description.place(anchor="nw", relx=0.08, rely=0.5)
      description_entry.place(anchor="ne", relx=0.92, rely=0.5)
      submit_button.place(anchor="n", relx=0.5, rely=0.75)
  </code></pre>
  
  <p>Here is the result of the execution of the script. Top window is the main window, bottom window is the TopLevel one. Backgrounds must be identic.
  I can't post images because my account is new but you'll find the result i got <a href="https://i.postimg.cc/XNCQHmKw/Screen-Shot004.png" rel="nofollow noreferrer">here</a>.
  Any ideas why it doesn't work ?</p>