Decode Base64 after it has been saved as a string object?

Question

I am fairly new to Python and am attempting to compile a text (.txt) document that acts as a save file and can be loaded later.

I would like it to be a standalone document that holds all attributes the user is working with (including some images that I would like to be saved in the file as encoded base64 binary strings).

I have written the program and it saves everything to the text file correctly (although I did have to pass the encoded values through a str()) but I am unable to access the images later for decoding. Here is an example of my creation of the text information:

if os.path.isfile("example.png"): #if the user has created this type of image..  
    with open("example.png", "rb") as image_file:
        image_data_base64_encoded_string = base64.b64encode(image_file.read())
        f = open("example_save.txt",'a+')
        f.write("str(image_data_base64_encoded_string)+"\n")
        f.close() #save its information to the text doc

And here is an example of one of my many attempts to re-access this information.

master.filename =  filedialog.askopenfilename(initialdir = "/",title = "Select file",filetypes = ((".txt files","*.txt"),("all files","*.*")))
with open(master.filename) as f:
    image_import = ((f.readlines()[3]))#pulling the specific line the data string is in

image_imported = tk.PhotoImage(data=image_import)

This is only my most recent attempt of many - and still returns an error. I tried decoding the encoded information before passing to the tkinter PhotoImage function but I think that Python may be seeing the encoded information as a string (since I made it one when I saved the information) but I do not know how to change it back without altering the information.

Any help would be appreciated.

Answer 1

I would recommend using Pillow module for working with images but if you insist on your current way try this code below:

from tkinter import *
import base64
import os

if os.path.isfile("example.png"): #if the user has created this type of image..  
    with open("example.png", "rb") as image_file:
        image_data_base64_encoded_string = base64.b64encode(image_file.read())
        f = open("example_save.txt",'a+')
       f.write(image_data_base64_encoded_string.decode("utf-8")+"\n")
       f.close() 

filename =  filedialog.askopenfilename(initialdir = "/",title = "Select file",filetypes = ((".txt files","*.txt"),("all files","*.*")))
with open(filename) as f:
    image_import = f.readlines()[3].strip()
image_imported = PhotoImage(data=image_import)

You see your string needs to be utf-8 and that trailing newline character is also preventing PhotoImage() from interpreting your image data as image.