Replace Duolingo cartoons with anime girls

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 2,
  "name": "Replace Duolingo cartoons with anime girls",
  "description": "Replace the cartoons in Duolingo exercises with anime girls.",
  "version": "1.1",
  "web_accessible_resources": [
    "duo.js",
    "source/*.png",
    "hide_images.css"
  ],
  "browser_action": {
    "default_icon": "icon.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.duolingo.com/*",
        "https://www.duolingo.com/practice",
        "https://www.duolingo.com/skill/*",
        "https://www.duolingo.com/learn"
      ],
      "js": [
        "loader.js"
      ],
      "css": [
        "hide_images.css"
      ]
    }
  ]
}