Надеюсь, это поможет людям, которые пытаются загрузить видео в Picasa с помощью .NET API.
RequestSettings mySettings = new RequestSettings("PROGRAM NAME");
mySettings.Timeout = 600000;
PicasaRequest pr = new PicasaRequest(mySettings);
PicasaService service = pr.Service;
service.setUserCredentials(username, password);
Uri postUri = new Uri(PicasaQuery.CreatePicasaUri(username, picasaalbumid));
PhotoEntry videoEntry = new PhotoEntry();
videoEntry.Title = new AtomTextConstruct(AtomTextConstructElementType.Title,"Untitled.3gp");//I would change this to read the file type, This is just an example
videoEntry.Summary = new AtomTextConstruct(AtomTextConstructElementType.Summary,"");
MediaFileSource source = new MediaFileSource(stream,fileName,fileType);
videoEntry.MediaSource = source;
PicasaEntry entry = service.Insert(postUri,videoEntry);
stream.Close();