Examine source code of LondonSkylineSil

{
  "theme": {
    "images": {
      "theme_frame": "TryAgain.png"
    },
    "colors": {
      "frame": "#e4e9eb",
      "tab_background_text": "#e892a5"
    }
  },
  "version": "2.0",
  "name": "LondonSkylineSil",
  "manifest_version": 2,
  "description": "Credit for original photo:\nB on <a href=\"https://outgoing.prod.mozaws.net/v1/da44f0f7f2d4f4767f3ca40c1d6a5ece8abe7d4b7bbdb4498b01d518ed9e88e8/http%3A//Clker.com\" rel=\"nofollow\">Clker.com</a>\n\n**I seriously cannot get this picture to center."
}