The author says:
Visionary inventor Nikola Tesla and his assistant Clara must use their extraordinary talents and devices to save Earth from alien invaders. This is a SF novel set in the early 1900s, with the themes of advanced ‘weird’ science, alien invasion, mind control, interdimensional travel and telepathic beings. The target audience is readers of classic SF, and any fan of Tesla, who is a cult favorite of nerds and New Agers alike.
The historical back-and-white photos look like they’d be more at home on a nonfiction book (especially the assissant Clara, since the poor quality of the photo makes it look like “this is the only documentation we have of her”). I’d say lose both photos, as they really don’t fit with the rest of the full-color cover. If you’re worried that that leaves the bottom half empty-looking, then move the Tesla tower further down the page, put your byline at the bottom (and make it bigger), put your blurb closer to the top, and increase the size of the title (which would also help correct the almost-but-not-quite-centered look). You might also want to experiment with making the dark blue even darker, and perhaps adding a subtle texture to it. (You could also play with adding a subtle texture to the main part of the Tesla tower; at full size, the computer-generated image looks a bit plain, and a slight texture could help set the tower off from the lightning emanating from it.)