Artist Eric Guerrero poses Harley Quinn in front of the Caped Crusader in this 18 x 24-inch poster. Stacking the characters this way strikes a nice contrast between Batman and Quinn, making the Dark Knight, devoid of color, look all the more menacing and gargoyle-like against Harley’s bright costume and playful demeanor, unfazed by the chaos of bats enveloping her.
The poster above is printed onto high quality thick Satin paper, and is available from Amazon. I've also included a variant version of the poster from Guerrero's DeviantArt page, where widescreen desktop versions of both designs are also available. Thanks to GeekAlerts for the find.