The background image for my custom tkinter program will not appear

Question

I am trying to put a background to my custom tkinter program. It has a main class that all my frames are add to. This same class has functions to make them appear. The problem is, is that instead of showing my background image, it just shows a gray box that all the frames are then placed on top of. Here is my code:

import customtkinter as ctk
from PIL import Image  # Required for handling images
from frames import *

ctk.set_appearance_mode('dark')
ctk.set_default_color_theme('dark-blue')

class FrameManager(ctk.CTk):
def __init__(self, debug_mode=False):
super().__init__()

        self.title('Equipment Manager')
        self.geometry('1000x580')
    
        # Add background image
        self.background_image = ctk.CTkImage(Image.open("EquipmentManager\\background.png"), size=(1000, 580))
        self.background_label = ctk.CTkLabel(self, image=self.background_image, text="")
        self.background_label.place(x=0, y=0, relwidth=1, relheight=1)
        self.background_label.lower() 
    
        # Configure layout grid
        self.grid_rowconfigure(0, weight=1)
        self.grid_columnconfigure(0, weight=1)
    
        # Create a dictionary for frames
        self.frames = {}
    
        # Add all the frames
        self.add_frame(LoginFrame, 'Login')
        self.add_frame(SignUpFrame, 'Sign Up')
        self.add_frame(LoadingFrame, 'Loading')
        self.add_frame(DatabaseFrame, 'Database')
        self.add_frame(ViewContactData, 'CData')
        self.add_frame(ViewEquipmentData, 'EData')
        self.add_frame(AddContact, 'AddC')
        self.add_frame(AddEquipment, 'AddE')
    
        # Debug mode
        self.debug_mode = debug_mode
        if self.debug_mode:
            self.frame_selector = ctk.CTkOptionMenu(
                self,
                values=list(self.frames.keys()),
                command=self.show_frame,
            )
            self.frame_selector.grid(row=0, column=1, padx=10, pady=10, sticky='e')
    
        # Show the first frame
        self.show_frame('Login')
    
    def add_frame(self, page_class, name):
        # Add frames and set transparency
        frame = page_class(self)
        frame.configure(fg_color="transparent")  # Ensure frames allow background to show
        self.frames[name] = frame
        frame.grid(row=0, column=0, sticky='nsew')
    
    def show_frame(self, name):
        # Raise the selected frame to the top
        self.frames[name].tkraise()
    
    def login_succesful(self):
        self.show_frame('Loading')
        self.frames['Loading'].animate_loading()

if __name__ == '__main__':
app = FrameManager(debug_mode=True)
app.mainloop()

The image does show where my debug menu appears, but not where the frames appear.