Fix incorrect return for manip command

src/Controllers/ImageManipulationController.cs

@@ -90,7 +90,7 @@ public class ImageManipulationController : BaseController<ImageManipulationContr
 					return HttpContext.SendStream(image, "image/png");
 				}
 
-				return result as IResult;
+				return result as ObjectResult;
 			}
 
 			return HttpContext.Send(EventResult.FromFailure("No template has been provided"), System.Net.HttpStatusCode.BadRequest);