From the website: “This collection provides access to thousands of items selected from the John Johnson Collection of Printed Ephemera, offering unique insights into the changing nature of everyday life in Britain in the eighteenth, nineteenth and early twentieth centuries. Categories include Nineteenth-Century Entertainment, the Booktrade, Popular Prints, Crimes, Murders and Executions, and Advertising.”
The collection is housed at the Bodleian Library in Oxford. There is a public-facing search page here: http://johnjohnson.chadwyck.co.uk/geoLocSubscription.do
If you are based in the UK you have free access to the collection. Click on the link at the bottom right (‘Access this collection’).
The website states that the images are “provided for internal research or educational use” only and that “No further reproduction or distribution is permitted.”
More information about the collection here: https://www.bodleian.ox.ac.uk/johnson