public async Task<bool> FavoriteImageAsync(string imageId)
{
if (string.IsNullOrWhiteSpace(imageId))
throw new ArgumentNullException(nameof(imageId));
if (ApiClient.OAuth2Token == null)
throw new ArgumentNullException(nameof(ApiClient.OAuth2Token), OAuth2RequiredExceptionMessage);
var url = $"image/{imageId}/favorite";
using (var request = RequestBuilder.CreateRequest(HttpMethod.Post, url))
{
var imgurResult = await SendRequestAsync<string>(request).ConfigureAwait(false);
return imgurResult.Equals("favorited", StringComparison.OrdinalIgnoreCase);
}
}