SetBackgroundWinsows.py

import json
import glob
import os 
import re
import random

## Get Settings.
dirname = os.path.dirname(os.path.realpath(__file__))
f = open(f'{dirname}/settings.json')
data = json.load(f)
profileGuid=data["ProfileGuid"]
terminalSettingsPath = data["TerminalSettingsPath"]
backgroundImagePath = data["BackgroundsPath"]
# Get JPGs and PNGs from image folder.
jpgs = glob.glob(f"{backgroundImagePath}/*.jpg")
pngs = glob.glob(f"{backgroundImagePath}/*.png")

jpgs.extend(pngs)
backgrounds = jpgs
f.close()

windowsPaths = list(backgrounds)

# Update settings.
with open(terminalSettingsPath, "r+") as f:
    data = json.load(f)
    profiles = data["profiles"]["list"]
    # Get profile with guid.
    elem = next(filter(lambda profile: profile["guid"] == profileGuid, profiles), None)
    random.shuffle(windowsPaths)
    # Find first non-matching image, don't want duplicates
    windowsPaths = [value for value in windowsPaths if value != elem["backgroundImage"]]
    elem["backgroundImage"] = windowsPaths[0]
    f.seek(0)        # <--- should reset file position to the beginning.
    json.dump(data, f, indent=4)
    f.truncate() 

settings.json

{
    "TerminalSettingsPath":  "C:\\Users\\Elmer\\AppData\\Local\\Packages\\Microsoft.WindowsTerminal_8wekyb3d8bbwe\\LocalState\\settings.json",
    "BackgroundsPath": "C:\\Terminal\\Backgrounds",
    "ProfileGuid":  "{61c54bbd-c2c6-5271-96e7-009a87ff44bf}"
}