Downloads and caches images or their errors.
 public ThreadPostBaseViewModel(string boardName)
 {
     this.BoardName = boardName;
     this.BitmapManager = Container.Resolve<BitmapManager>();
     this._urlBuilder = Container.Resolve<DvachUrlBuilder>();
     this._youtubeHelper = Container.Resolve<YoutubeHelper>();
 }
 public ThreadListViewModel()
 {
     this.Threads = new ObservableCollection<ThreadItemViewModel>();
     this._bitmapManager = Container.Resolve<BitmapManager>();
     this._urlBuilder = Container.Resolve<DvachUrlBuilder>();
 }