Ein geoJSON Overlay über die Grundkarte könnte geeignet sein. https://help.github.com/articles/mapping-geojson-files-on-github/

There is also a database of georeferenced photos related to bicycle infrastructure at http://www.cyclestreets.net/api/v2/photomap.location/

Very nice. I started adding pictures around here to cyclestreets. They have a nice API for geocoded cycle related pictures, maybe you can cooperate.