I made this little program in a few hours to make wallpapers of the /r/ImagesOfEarth subreddit automatically downloading.

When you start the program, it will create a "settings.ini" file, and automatically starts downloading the newest 15 images to a "wallpapers" folder located near the program file. After it's done, by default, it will show a small form to configure the program. If you want to start the program on system startup, provide the "silent" parameter to the program to prevent the GUI from loading and thus just sync the wallpapers.