Examine source code of Image Dimensions

{
  "name": "Image Dimensions",
  "version": "1.0.0.1",
  "author": "Genius Lynx",
  "description": "Get current page image dimensions (width x height) from images loaded in the DOM [Document Object Model - img tag]",
  "browser_action": {
    "default_icon": "icon.png",
    "default_popup": "popup.html",
    "default_title": "Image Dimensions"
  },
  "icons": {
    "16": "icon16.png",
    "48": "icon48.png",
    "128": "icon128.png"
  },
  "permissions": [
    "activeTab"
  ],
  "browser_specific_settings": {
    "gecko": {
      "id": "geniuslynxhelpdesk@gmail.com",
      "strict_min_version": "57.0"
    }
  },
  "content_scripts": [
    {
      "matches": [
        "<all_urls>"
      ],
      "js": [
        "purify.min.js"
      ]
    }
  ],
  "manifest_version": 2
}