Pow indeed. 1966.
Something else a little different: The production art for the (North American) cover of Jimi’s debut. In Olden Times, the tissue overlay like this was used to indicate where and how color is applied, and also where to place other camera-ready bits of art (like the word “Stereo”, the “Printed in the U.S.A.” line, and the Reprise logo) indicated here with little sketches. The art under the tissue was likely the final version to be shot for the film and printing plates (though full color separations would be swapped in for the image, which was printed in color.) Here’s the final product, for your reference.
Saw this at the Experience Music Project. From 1967. Cover photo & design by Karl Ferris.