Google made available the "Photos layer" from Google Maps to Maps API developers, that adds thumbnails of geotagged photos to the map, sourced from Panoramio.
"They're a great way to add additional context to a map, and an on the ground perspective. Photos can be added to an API map using the PanoramioLayer class of the new Panoramio library. We've also added some additional flexibility to enable you to customize both the behaviour of the layer and the thumbnails shown by your app," stated Google.
"Firstly, apps can listen for clicks on the photo thumbnails and obtain info about the thumbnail concerned, which can then be used to load photo using Panoramio Widget API. Secondly, apps can also restrict thumbnails shown to those of a particular user, or those with a particular tag. This allows you to only show thumbnails for photos that you've uploaded to Panoramio, or only show photos relating to a specific subject, such as beaches."
You can try experimenting with different tags in the example below:
For more information on using the PanoramioLayer, take a look at the Maps API documentation.