Bellicose is about an Imperial Postal Marine: Danel Bophendze. He joins the Postal Marines as an orphan (16yo), and embeds an artificial intelligence (AI) in his brain to make up for his deficiencies. He spends the rest of his life battling the psychosis of having a powerful intellect, while at the same time becoming a legend.
This milieu is set about 1900 years in the future, but fairly distopian. Faster-than-light travel is a complex "hop" that has a low probability of failure that (effectively) destroys the ships.
The Postal Marines are somewhere between the National Guard and the Coast Guard...they have their own space ships and tend to be ship-combat focused. They interdict smugglers, perform rescues and stop pirating. They wear body-tight battle armor with helmets & HUD (capable of limited space survivability and flight). Their ships are small to medium in size.
However, by the end of the novel, the Postal Marines form as a fleet (first time ever) and take on a portion of the Imperial Navy, who tend to operate using large ships. The Navy engages in system-wide subjugation, planetary bombardments, and planetary battle/occupation. The Navy knows they are coming and are prepared to slaughter them.
Instead, Bophendze boards the Navy flagship by going down a 720mm cannon barrel between shots. I always thought it would be interesting to see a graphic of him at the gun's muzzle preparing to fly down the barrel.
Book Size: 6"x9" with the image size of 9.25" x 12.85" @ 300dpi, which includes a bleed of 0.125" on all sides. I calculate that at about 3855 pixels wide by 2800 pixels high.