We are needing to grab a thumbnail image of our documents on Google Could Storage for use in our Drupal module. Previously https://docs.google.com/viewer?url=DOC_STORAGE_URL&a=bi&pagenumber=1 worked for us, but the google viewer seems to no longer support the a=bi parameter.
Does anyone have any information about the viewer no longer generating a thumbnail, or know if there is a way to grab a thumbnail image of the document stored on Google Could Storage using its API like you can with the Drive API? We are currently using the google-api-php-client. https://developers.google.com/drive/v2/reference/files
Google Cloud Storage does not generate thumbnails for any objects. You would need to generate these thumbnails, upload them to Google Cloud Storage, and then reference them yourself.
As @rein said, GCS doesn't generate thumbnails for any object. But there is an alternative: the Images API. Although is not available for PHP, if you can write in Python [1] or JAVA [2] this library contains the functionality you are looking for.
Check the function get_serving_url here [3]. It will generate an url that accepts parameters. Specifically, the parameter =sXX will generates thumbnails of XX pixels (on the longest dimension).
[1] https://cloud.google.com/appengine/docs/python/images/
[2] https://cloud.google.com/appengine/docs/java/images/
[3] https://cloud.google.com/appengine/docs/python/images/functions