Hi! Thank you for your openness for your previous issue which you accepted.
In resources/application.properties you provide the urls to download wallpapers from. There are so 4 urls from which the program downloads wallpapers over HTTP. Why are you not using HTTPS for all URLs? I have tested that and it still works.
There is a small typo in the wiki title: WallpapeDownloader missing the letter r.
Perhaps in the future i'd like to create pull requests if possible but that is not allowed now.