private async void PickPhotoCommandExecute()
        {
            try
            {
                var action = await DisplayPictureAlert();

                var pictureService = Xamarin.Forms.DependencyService.Get <PictureService>();
                var file           = await pictureService.GetPicture(action);

                if (file != null)
                {
                    using (var memoryStream = new MemoryStream())
                    {
                        file.GetStream().CopyTo(memoryStream);
                        file.Dispose();
                        PetImages.Add(new PetPictureItem
                        {
                            Id    = Guid.NewGuid().ToString(),
                            Image = memoryStream.ToArray()
                        });
                        CreatePosterCommand.RaiseCanExecuteChanged();
                    }
                }
            }
            catch (Exception ex)
            {
                await _dialogService.DisplayAlertAsync("Erro", ex.Message, "Fechar");
            }
        }
 private void DeletePetPictureCommandExecute(string imageId)
 {
     PetImages.Remove(PetImages.Single(w => w.Id == imageId));
     CreatePosterCommand.RaiseCanExecuteChanged();
 }