According to the Valiant marketing annual given to retailers at the Capital City Distributors conference explaining Valiant's upcoming releases and promotions, this is the second of two point of purchase posters supporting the UNITY crossover. It shipped with Valiant's April solicitations. The image is the same as the cover to Eternal Warrior #1 and is by famed creator Frank Miller.
The other poster is a Barry Windsor-Smith UNITY poster that shipped with Valiant's March solicitations. That features the same art as the cover of UNITY #0.