WallHaven Desktop Client, Cross Platform and open source.

I think this project of yours looks really cool. I must admit though, the most exciting feature for me is the option to download multiple wallpapers at once.

I'm not the biggest fan of using bootstrap though, not that I don't see it's use. It can be quite practical and timesaving. Overall I think you've done a good job (looking at the code). Music player eh? Haha, that's a little too much.