Costume Design by Jeffrey Kurland and Anna B. Sheppard. I'm not sure who did these, but they list
James Carson and
Rodolfo Damaggio as the concept artists



A couple of things I like are the almost accidental inclusion of Captain America concept elements like the red and white stripes on the tunic. and the muted colors. Most notably missing are the wings on the helmet. This is probably a good idea since they'd get blown off by weapons fire anyway. Overall, it looks good.
I find it interesting that Marvel is using computer graphics to create the "concept art" for their upcoming movies. I hope it's not a trend since I prefer hand-drawn art.