So I found out about the postcards. All I had to do was type "W.J. Grimshaw" and postcards into google and it took me to the Grimshaw family page. I always feel extra stupid when it takes me a week to actually do the five seconds of work needed to solve a problem or answer a question.
William Grimshaw was born on October 14, 1830 in Accrington, Lancashire and emigrated to the U.S. in about 1847. After living for a brief time in Pennsylvania, he moved to Bordentown, New Jersey where he apparently married Emily Brown in 1853. After living there for more than 20 years, the family relocated to Staten Island in 1873, where William was engaged as a carpenter for the remainder of his life. William and Emily had at least four children -- William J., Frank P., Lamar C., and Margaret Grimshaw. William died in 1905 and Emily passed away in 1908. William's oldest son, William J., operated a stationery and confectionery business that became later focused on selling ice cream when it was first introduced.
Now Mr. Grimshaw and his son's postcards are collected for our pleasure on the NYPL's Digital Collection pages. I've said it before, check them out.