London Underground walking times station map
I mentioned this map before ("Showing walk times on transit maps") London Underground produced a station map listing the walk times between stations, because people unfamiliar with the system don't necessarily realize that rather than transfer between lines to get to a final destination, sometimes rather than transferring it's faster to walk. (This is the case in the DC Metrorail system between Gallery Place and Metro Center in particular.)
But I bring it up again because I was introduced to a great online tool which converts pdfs to jpgs, created by Investintech. Investintech also produces a desktop program which can extract individual pdf pages from large files and convert them to jpgs too, as part of a long list of other useful online conversion tools.
Here is the pdf version of the London Underground walking map, with the jpg format shown below, as converted by the Investintech software tool.