YouTube Thumbnail Preview

manifest.json

{
  "update_url": "https://clients2.google.com/service/update2/crx",
  "manifest_version": 3,
  "name": "YouTube Thumbnail Preview",
  "version": "2.1",
  "description": "Replaces a thumbnail on the YouTube homepage with a local image.",
  "action": {
    "default_popup": "popup.html",
    "default_icon": {
      "16": "icon16.png",
      "48": "icon48.png",
      "128": "icon128.png"
    }
  },
  "permissions": [
    "storage",
    "scripting"
  ],
  "host_permissions": [
    "*://*/*"
  ],
  "background": {
    "service_worker": "background.js"
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "content_scripts": [
    {
      "matches": [
        "https://www.youtube.com/*"
      ],
      "js": [
        "content_script.js"
      ]
    }
  ]
}