NatureSearch | Custom Nature Backgrounds

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "name": "NatureSearch | Custom Nature Backgrounds",
  "version": "1.6",
  "description": "This extension creates a nature background whenever a new tab is opened. It's changeable.",
  "permissions": [
    "bookmarks",
    "declarativeContent",
    "activeTab"
  ],
  "background": {
    "scripts": [
      "background.js"
    ],
    "persistent": false
  },
  "page_action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "images/get_started16.png",
      "32": "images/get_started32.png",
      "48": "images/get_started48.png",
      "128": "images/get_started128.png"
    }
  },
  "icons": {
    "16": "images/get_started16.png",
    "32": "images/get_started32.png",
    "48": "images/get_started48.png",
    "128": "images/get_started128.png"
  },
  "content_security_policy": "script-src 'self' https://code.jquery.com/jquery-3.2.1.slim.min.js https://maxcdn.bootstrapcdn.com/bootstrap/4.0.0/js/bootstrap.min.js https://cdnjs.cloudflare.com/ajax/libs/popper.js/1.12.9/umd/popper.min.js; object-src 'self'",
  "chrome_url_overrides": {
    "newtab": "startpage/index.html"
  },
  "manifest_version": 2
}