https://whitmanarchive.org/criticism/current/anc.00150.html

For the first time the publisher's name appears prominently on the title page. Though the edition was actually published in 1860, the title page asserts that the edition was published in the "Year 85 of The States. / (1860⋏61)," indicating Whitman's decision to use a new American calendar and date his publications from the Declaration of Independence. The book features a new frontispiece engraving of Whitman produced by S. A. Schoff (based on a painting by Charles Hine, which itself may have been based on a photograph of Whitman taken in the late 1850s), which sharply contrasts with the engraving used in the previous two editions of Leaves of Grass (fig. 16). The Schoff engraving gives us a more elegant and full-faced Whitman, presumably sitting, with shirt, jacket, and tie. Schoff's engraving appeared in three forms, because he was not finished with the engraving when the volume was ready for binding, so the various issues contain increasingly more finished states of the engraving.