Update to upfile again.

lib/paperclip/upfile.rb

@@ -9,7 +9,8 @@ module Paperclip
       type = (self.path.match(/\.(\w+)$/)[1] rescue "octet-stream").downcase
       case type
       when %r"jpe?g"                 then "image/jpeg"
-      when %r"png", "gif", "bmp", "tiff" then "image/#{type}"
+      when %r"tiff?"                 then "image/tiff"
+      when %r"png", "gif", "bmp"     then "image/#{type}"
       when "txt"                     then "text/plain"
       when %r"html?"                 then "text/html"
       when "csv", "xml", "css", "js" then "text/#{type}"