I was looking for images of Harpers Ferry, West Virginia, and I found several interesting ones on the Library of Congress website. While none are from John Brown’s attack in October 1859, these are related to it.
Before the raid, Brown and his men lived for several months at the Kennedy Farm in Maryland:
PBS also has an interesting site on the Kennedy Farm: http://www.pbs.org/wgbh/amex/brown/sfeature/kennedyfarm.html
The Library of Congress also has an image of the engine house (from 1865) where Brown was captured by the US military: