diff --git a/middleman-more/lib/middleman-more/extensions/automatic_image_sizes.rb b/middleman-more/lib/middleman-more/extensions/automatic_image_sizes.rb
index 78a45f3f..58e52f71 100644
--- a/middleman-more/lib/middleman-more/extensions/automatic_image_sizes.rb
+++ b/middleman-more/lib/middleman-more/extensions/automatic_image_sizes.rb
@@ -51,6 +51,8 @@ module Middleman
               end
             end
           end
+          
+          params = params.delete_if {|key| key == :supported_extensions }
 
           super(path, params)
         end