Photoshop decided it was smarter than me and would override my decisions about exporting a PNG layer with transparencies. It’d clip it and mess up my careful alignment. You can see someone else suffering from this on the Adobe forums. This could not stand. If you don’t want to see the setup for the issue and just want the answer . . . take the paint brush set the opacity to 0 and make a slash across the top prior to export.
I’ve taken a fair number of public domain photos and dropped the backgrounds so I could use them in various projects. I figured they might be of use to some other people out there. If you click through to the largest image size you’ll find they are decently done (not perfect by any means) but the smaller versions auto generated by Flickr look like COMPLETE garbage. I’m not sure why. But they are PNG files so you can clean them up some more pretty easily if you’d like. The flickr set is here. Most of the ones up there right now are history related and it’ll likely stay that way for the immediate future.