1 files changed, 18 insertions, 1 deletions
diff --git a/ext/tk/lib/tk/image.rb b/ext/tk/lib/tk/image.rb
index 57f82cb812..dffdc19644 100644
--- a/ext/tk/lib/tk/image.rb
+++ b/ext/tk/lib/tk/image.rb
@@ -156,7 +156,7 @@ class TkPhotoImage<TkImage
     self
   end
 
-  def cget(option)
+  def cget_strict(option)
     case option.to_s
     when 'data', 'file'
       tk_send 'cget', '-' << option.to_s
@@ -164,6 +164,23 @@ class TkPhotoImage<TkImage
       tk_tcl2ruby(tk_send('cget', '-' << option.to_s))
     end
   end
+  def cget(option)
+    unless TkConfigMethod.__IGNORE_UNKNOWN_CONFIGURE_OPTION__
+      cget_strict(option)
+    else
+      begin
+        cget_strict(option)
+      rescue => e
+        if current_configinfo.has_key?(option.to_s)
+          # error on known option
+          fail e
+        else
+          # unknown option
+          nil
+        end
+      end
+    end
+  end
 
   def copy(src, *opts)
     if opts.size == 0