Walter Baker Chocolate & Co. began at Lower Mills in 1780. By the mid-19th century they began to advertise in print. Their adoption in 1862 of the portrait of La Belle Chocolatiere as their logo in the coincided with a period of growth in illustrated advertising, especially in national magazines. As the quality of printing in color became widespread, Baker Chocolate consistently offered fresh illustrations for their advertisements, always including at least a silhouette of La Belle Chocolatiere.
For the date of the adoption of the portrait as a logo by Baker, see https://archive.fo/20120905171335/http://www.mce.k12tn.net/chocolate/history/history_of_chocolate5.htm