Fix issue #125

Former-commit-id: 3d88825a483ed7a214b6614f0eae52778b504e92
Former-commit-id: c538ee57e5a4d9512931cc9f4b79fc24fc4532dc

src/ImageProcessor.Web/Helpers/ImageHelpers.cs

@@ -67,7 +67,7 @@ namespace ImageProcessor.Web.Helpers
 
             // First check to see if the format processor is being used and test against that.
             IWebGraphicsProcessor format = ImageProcessorConfiguration.Instance.GraphicsProcessors
-                                           .First(p => typeof(Format) == p.GetType());
+                                           .FirstOrDefault(p => typeof(Format) == p.GetType());
 
             if (format != null)
             {