It seems that the .NET library for the Picasa Web Albums API is unable to set the Published date of an album.

Ie, after executing the following code…

AlbumEntry newEntry = new AlbumEntry();
newEntry.Title.Text = "Example";
newEntry.Published = new DateTime(2000, 1, 1);

ac = new AlbumAccessor(newEntry);
ac.Access = "public";

Uri feedUri = new Uri(PicasaQuery.CreatePicasaUri("username");
PicasaEntry createdEntry = picasaService.Insert(feedUri, newEntry);

…  createdEntry.Published would be something close to DateTime.Now.

I eventually found a solution here; http://markmail.org/message/767tsxpmungs4x3i

But it took me a bit of wasted debugging and searching with different keywords, so I hope this post contributes towards an easier-to-find solution for someone else :-)

So the modifications I would make to the above example would be something like:

 

AlbumEntry newEntry = new AlbumEntry();
newEntry.Title.Text = "Example";
newEntry.Published = new DateTime(2000, 1, 1);

// needs to be set as UNIX timestamp
DateTime origin = new DateTime(1970, 1, 1, 0, 0, 0, 0);
TimeSpan diff = newEntry.Published.Subtract(origin);
double timestamp = Math.Floor(diff.TotalMilliseconds);

newEntry.SetPhotoExtensionValue("timestamp", timestamp.ToString());

ac = new AlbumAccessor(newEntry);
ac.Access = "public";

Uri feedUri = new Uri(PicasaQuery.CreatePicasaUri("username");
PicasaEntry createdEntry = picasaService.Insert(feedUri, newEntry);