The top image is a General Dynamics postcard by Erik Nitsche. The lower is from Joel Johnson’s flickr page. The background illustrations in each appear to be essentially identical save for some rotation. If you look closely at the children in the lower one you can see they are superimposed rather poorly (note the black outline from the sloppy clipping path). I wonder if this was someone appropriating the artwork or if this was some General Dynamics-sanctioned variation of the original (doubt it). Interesting either way; I think I like the yellowed, saturated version on the bottom best. The composition of the top example, of course, is superb.