var pageSettings={
  red: 200,
  green: 200,
  blue: 200,
  background: ['https://pictures.s3.yandex.net/background.jpg', 'https://pictures.s3.yandex.net/cover-color.jpg', 'https://pictures.s3.yandex.net/cover-grid.jpg', 'https://pictures.s3.yandex.net/cover-typo.jpg', 'https://pictures.s3.yandex.net/cover-wall.jpg']
};
var bgColor="rgb(" + pageSettings.red + ',' + pageSettings.green + ',' + pageSettings.blue + ')';
document.body.style.backgroundColor=bgColor;
var header=document.getElementById('main-header');
console.log(header);
header.style.backgroundImage='url('+pageSettings.background[2]+')';