Here is a tutorial to host the icons on your Google Drive account:
1/ Inside Google Drive, create a folder called “MapIconsCollection”
2/ Right-click on the folder “MapIconsCollection”,and use the “Share” menu, a popup will open, change “Who has access” into “Public on the web”
3/ Don’t close the popup, click “Copy Link”. This will copy a link like:
https://drive.google.com/folderview?id=0B21DW8BAAHkZdzU3ZUJFTWk3b1U&usp=sharing with 0B21DW8BAAHkZdzU3ZUJFTWk3b1U being the docid of my folder. Yours will be a different.
4/ Enter the folder “MapIconsCollection”
5/ Now download some icons you need
6/ Upload the icons into the “MapIconsCollection” folder
7/ Now go to the URL:
http://www.googledrive.com/host/[docid] with [docid] being your docid. The following page will list all the icons in your folder.
8/ For each icon, left-click on the filename of the icon, and “Copy Link Address”.
9/ Now you can paste the URL in Google Maps or other maps applications.
Tutorial updated on January 27th 2015.