Here are some very neat photos of the XB-19 of either specific points of interest or rare photos I think are interesting:
Photograph of the upper front turret, which had one 37 mm cannon and one .30 Cal machine gun. You can actually see how one would aim the turret, and its interesting how it uses a rifle butt or stock.
Then in this photo you get a look at the tail gunner position. There was a catwalk that led from the galley to the impressively spacious tail gunner area.
In this next photo you see the B-19 from an angle you don't usually see, In this photo you can see on the side right behind the USAAF Roundel you can see the hole where a .30 cal Browning machine would go. You can also below that see the "lower rear manual turret" which was a .50 Cal Browning Machine gun, the gunner would be leaning against a support to hold and aim it.