This is the most famous abolitionist image. It was originally created by Thomas Wedgewood for England's Anti-Slavery Society; in the 1830s the American Anti-Slavery Society adopted it as the emblem of their cause. The Editors of the definitive University of California edition of Huck Finn suggest that Kemble's drawing of Jim on his knees to Huck "quotes unmistakably" from this image, "one of the most widely known graphic symbols of the campaign to abolish slavery." Soon after meeting Jim on Jackson's Island, Huck does promise to help him run away from slavery, but in the drawing we don't just see Jim kneeling in supplicant -- we also see a white person standing over him with a gun, which at least complicates that Anti-Slavery image.
(Berkeley: The Mark Twain Library, 2001)