This makes perfect sense. Why wouldn't a lady keep a revolver nearby while she's taking a shower? Lather, rinse, lock and load, repeat. 1947.
A nice stylization of the theme. 1954.
It's 1959, and someone at Pocket Books decided to drop the shower curtain-firearms theme for this dame in a magician's cape and skin-tight, off-the-shoulders unitard. Bad call. The big .44 revolver has been downsized to a tiny Luger-style derringer, which might stop the neighbor's poodle, but not much else.
I'm guessing the hat and cane on the chair means her boyfriend is Sebastian Cabot?
A return to the theme, thankfully. Now she's Barbara Feldon in a beehive. Glad to see she wised up and decided to go with the big-calibre revolver again. 1964.