Halve the eggs lengthwise. Remove the yolks and add them to a medium bowl. Mash the yolks with a fork and stir in the mayonnaise, bacon, tomatoes, and parsley. Add salt and pepper, to taste, and blend well.
Fill the egg whites evenly with the yolk mixture and garnish with bacon, if desired. Arrange them in a container and store, covered, in the refrigerator until ready to serve.