To use this, pass the ID of the My Map via the "&id=" parameter. You can find the ID in the "&msa=" parameter when you are viewing a map and click "Link to this page". It will turn the markers, paths, and polygons into a static map, using the Static Maps API v2. Keep in mind that many browsers have a max URL length for images, so there is a limit to how many overlays will fit into a static map URL.
You can try these IDs:
You can download the source code and modify it for your own needs.