title: How to update the timestamp on a photo or add the time zone on Google+ Photos?
body: <p>Using Picasa Web API I retrieve a photo from my Google+ photo album and attempt to change the timestamp (the time was wrong on my phone, so trying to fix it):</p>
  
  <pre><code>var service = new PicasaService("exampleCo-exampleApp-1");
  service.setUserCredentials("uid", "pwd");
  AlbumQuery query = new AlbumQuery(PicasaQuery.CreatePicasaUri("default"));
  
  PicasaFeed feed = service.Query(query);
  var entry = (PicasaEntry)feed.Entries.SingleOrDefault(f =&gt; f.Title.Text == "Trip to Italy - ALL");
  
  var ac = new AlbumAccessor(entry);
  
  var photoQuery = new PhotoQuery(PicasaQuery.CreatePicasaUri("default", ac.Id));
  PicasaFeed photoFeed = service.Query(photoQuery);
  
  PicasaEntry picasaEntry = photoFeed.Entries[0];
  
  ulong timestamp = Convert.ToUInt64(picasaEntry.GetPhotoExtensionValue("timestamp"));
  
  // deduct 9 hours
  DateTime dt = FromUnixTime(pa.Timestamp).AddHours(-9);
  picasaEntry.SetPhotoExtensionValue("timestamp", Convert.ToString(ToUnixTime(dt)));
  
  var updatedEntry = (PicasaEntry) picasaEntry.Update();
  </code></pre>
  
  <p>Unfortunately, while the .Update method succeeds, the timestamp doesn't change. 
  I've also tried to change the timezone of the photo (e.g. same thing user does manually like this <a href="http://i.imgur.com/pxYSi9S.png">http://i.imgur.com/pxYSi9S.png</a>).</p>
  
  <p>Am I missing something simple?
  Is there another way to accomplish the same thing?  I would also settle for changing the timezone of the photo.</p>