vary current background
export current background
close export menu
Click the share button. It's a link, so ctrl+click or middle click on the share 'button' works as well. From there you can either export the background as a free lower resolution PNG image or pay for the selected resolution as a PNG or vector image (SVG).
All the images you generate with this (web)application are under your copyright. Just like other applications such as Adobe Photoshop, Inkscape or Krita.