markers.js

var markers={
  "Kalimdor": [
    {
      "createInfoWindow": true, 
      "icon": "chest.png", 
      "displayName": "Locations", 
      "groupName": "Towns-Kalimdor"
    }, 
    {
      "createInfoWindow": true, 
      "icon": "photo.png", 
      "displayName": "Photos", 
      "groupName": "Screenshots-Kalimdor"
    }
  ], 
  "Azeroth": [
    {
      "createInfoWindow": true, 
      "icon": "chest.png", 
      "displayName": "Locations", 
      "groupName": "Towns-Azeroth"
    }, 
    {
      "createInfoWindow": true, 
      "icon": "photo.png", 
      "displayName": "Photos", 
      "groupName": "Screenshots-Azeroth"
    }
  ]
};

markersDB.js

var markersDB={
  "Towns-Kalimdor": {
    "raw": [
      {
        "y": 64, 
        "text": "Chichen Itza", 
        "z": -200, 
        "icon": "http://google-maps-icons.googlecode.com/files/ancienttemple.png", 
        "x": -150
      }
    ], 
    "name": "Locations", 
    "created": false
  }, 
  "Screenshots-Kalimdor": {
    "raw": [
      {
        "y": 58, 
        "text": "Here is a title <br><img width='350' height='250' src='http://i.imgur.com/9MqwRl.jpg'>", 
        "z": -90, 
        "icon": "photo.png", 
        "x": 34
      },
      {
        "y": 64, 
        "text": "Here is a second image<br><img width='350' height='250' src='http://i.imgur.com/9MqwRl.jpg'>", 
        "z": -90, 
        "icon": "photo.png", 
        "x": 34
      }
    ], 
    "name": "Photos", 
    "created": false
  }, 
  "Towns-Azeroth": {
    "raw": [
      {
        "y": 64, 
        "text": "Some Giant Castle", 
        "z": -90, 
        "icon": "http://google-maps-icons.googlecode.com/files/castle.png", 
        "x": 34
      }
    ], 
    "name": "Locations", 
    "created": false
  }, 
  "Screenshots-Azeroth": {
    "raw": [
      {
        "y": 58, 
        "text": "Here is a title <br><img width='350' height='250' src='http://i.imgur.com/9MqwRl.jpg'>", 
        "z": -90, 
        "icon": "photo.png", 
        "x": 34
      }
    ], 
    "name": "Photos", 
    "created": false
  }
};

For the list of dictionaries in the 'raw' field of markersDB, please use this new template:

{
        "y": 64, 
        "imgurl": "http://i.imgur.com/foo.png", 
        "linkurl": "http://foo.com/bar.html",
        "title": "Title",
        "desc": "Description"
        "z": -200, 
        "icon": "http://google-maps-icons.googlecode.com/files/ancienttemple.png", 
        "x": -150
      }

The title will be displayed in the marker alttext, and at the top of the popup info window. the description will only be displayed in the popup info window (and can be optional)