Hey there! Let's get your image viewer showing the right descriptions for each photo. I went through your code and found a few key issues that are preventing your custom text from appearing correctly:

Key Problems to Fix #

• Your des_list is filled with numbers ([1,2,3]) instead of the actual description text you wrote
• You defined des1, des2, des3 as labels but never used their text content
• The back function is missing entirely (so your Previous button would throw an error)
• When on the third image, you incorrectly disabled the Previous button

Step-by-Step Fixes #

1. Update the Description List #

Replace your current des_list with the actual description strings (you don't even need the des1/des2/des3 labels anymore):

# Replace this:
des_list = [1 , 2, 3]
# With this:
des_list = ["I am happy this day", "going somewhere", "Today is a great day"]

2. Fix the Forward Function's Description Logic #

In your forward function, update how you set the description text to use the actual strings from des_list:

# Replace this line:
my_des = Label(frame1, text = f"Description{des_list[image_num-1]}")
# With this:
my_des = Label(frame1, text=des_list[image_num-1])

3. Add the Missing back Function #

You need to define a back function to handle the Previous button clicks—add this right after your forward function:

def back(image_num):
    global my_label
    global prev
    global next1
    global num
    global my_des
    global des_list
    my_label.pack_forget()
    my_label = Label(frame1, image=img_list[image_num-1])
    my_label.pack()
    my_des.pack_forget()
    my_des = Label(frame1, text=des_list[image_num-1])
    my_des.pack()
    next1 = Button(frame2, text="Next", command=lambda: forward(image_num+1))
    next1.grid(row=1, column=2)
    prev = Button(frame2, text="Previous", command=lambda: back(image_num-1))
    prev.grid(row=1, column=0)
    # Disable Previous button when on first image
    if image_num == 1:
        prev = Button(frame2, text="Previous", state=DISABLED)
        prev.grid(row=1, column=0)

4. Fix the Third Image Button State #

In your forward function, when on the third image, don't disable the Previous button—only disable the Next button:

# Replace this:
if image_num == 3:
    next1 = Button(frame2, text = "Next", state = DISABLED)
    next1.grid(row = 1, column = 2)
    prev = Button(frame2, text = "Previous", state = DISABLED, command =lambda : back(2))
    prev.grid(row = 1, column = 0)
# With this:
if image_num == 3:
    next1 = Button(frame2, text="Next", state=DISABLED)
    next1.grid(row=1, column=2)
    # Keep Previous button enabled to go back to image 2
    prev = Button(frame2, text="Previous", command=lambda: back(2))
    prev.grid(row=1, column=0)

5. Initialize the Previous Button #

Add an initial disabled Previous button when the app starts (since you can't go back from the first image):

# Add this line after creating the next1 button
prev = Button(frame2, text="Previous", state=DISABLED)
prev.grid(row=1, column=0)

Full Modified Code #

Here's the complete fixed code with all the changes applied:

from tkinter import *
from PIL import Image, ImageTk

root = Tk()
root.title("Image Viewer")
root.config(bg="Grey")

frame1 = Frame(root, width=500, height=325, bg="Silver")
frame1.pack(side=TOP)
frame2 = Frame(root, width=500, height=25, borderwidth=1, bg="Grey")
frame2.pack(side=BOTTOM, pady=2)

# Images
img1 = ImageTk.PhotoImage(Image.open("dec19.jpg"))
img2 = ImageTk.PhotoImage(Image.open("dec20.jpg"))
img3 = ImageTk.PhotoImage(Image.open("dec21.jpg"))

# Description list (actual text for each image)
des_list = ["I am happy this day", "going somewhere", "Today is a great day"]

num = 1
img_list = [img1, img2, img3]

# Startup widgets
my_label = Label(frame1, image=img1)
my_label.pack()
my_des = Label(frame1, text=des_list[num-1])
my_des.pack(side=BOTTOM)

# Command functions
def close_app():
    root.quit()  # Better to use root.quit() than exit() for Tkinter apps

def forward(image_num):
    global my_label
    global prev
    global next1
    global num
    global my_des
    global des_list
    
    my_label.pack_forget()
    my_label = Label(frame1, image=img_list[image_num-1])
    my_label.pack()
    
    my_des.pack_forget()
    my_des = Label(frame1, text=des_list[image_num-1])
    my_des.pack()
    
    next1 = Button(frame2, text="Next", command=lambda: forward(image_num+1))
    next1.grid(row=1, column=2)
    prev = Button(frame2, text="Previous", command=lambda: back(image_num-1))
    prev.grid(row=1, column=0)
    
    if image_num == 3:
        next1 = Button(frame2, text="Next", state=DISABLED)
        next1.grid(row=1, column=2)
        prev = Button(frame2, text="Previous", command=lambda: back(2))
        prev.grid(row=1, column=0)

def back(image_num):
    global my_label
    global prev
    global next1
    global num
    global my_des
    global des_list
    
    my_label.pack_forget()
    my_label = Label(frame1, image=img_list[image_num-1])
    my_label.pack()
    
    my_des.pack_forget()
    my_des = Label(frame1, text=des_list[image_num-1])
    my_des.pack()
    
    next1 = Button(frame2, text="Next", command=lambda: forward(image_num+1))
    next1.grid(row=1, column=2)
    prev = Button(frame2, text="Previous", command=lambda: back(image_num-1))
    prev.grid(row=1, column=0)
    
    if image_num == 1:
        prev = Button(frame2, text="Previous", state=DISABLED)
        prev.grid(row=1, column=0)

# Buttons
exits = Button(frame2, text="Exit", command=close_app)
exits.grid(row=1, column=1)

next1 = Button(frame2, text="Next", command=lambda: forward(2))
next1.grid(row=1, column=2)

prev = Button(frame2, text="Previous", state=DISABLED)
prev.grid(row=1, column=0)

root.mainloop()

Extra Tips #

• I replaced exit() with root.quit() in the close_app function—it's the proper way to close a Tkinter app without causing unexpected behavior.
• You can customize the description labels further (add font, color, etc.) by passing parameters like font=("Arial", 12) or fg="blue" to the Label constructor.

Give this code a run, and you should see each image display its matching description as you navigate with the Next/Previous buttons. Let me know if you hit any other snags!

内容的提问来源于stack exchange，提问作者Anon Dorse