Thread:Tent2/@comment-27941806-20160730011537/@comment-25413737-20160730031920

I never used Paint.net but i'm gonna take a guess.

1st check your layers (if any), and delete the bottom most layer which i'm guessing contains all the 'white space'

Once deleted, save the image as a PNG, if the option is there make sure it's transparent or Interlaced.

Upload and see if that background is now the same as the page.

Congrats, it's transparent.