private void TwoPointOpWithDialog() { string fileName = OpenImage(); if (fileName == "fail") { return; } try { Bitmap overlayBitmap = new Bitmap(fileName, true); mainImage.overlayBitMap = mainImage.ConvertTo8bpp(new Bitmap(overlayBitmap, mainImage.imageBitMap.Size)); mainImage.OperationArithmeticLogical((operationName)cbTwoPointOp.SelectedIndex); } catch (Exception exception) { MessageBox.Show(exception.Message, "Exception"); } }