Marvel Studios released two new Avengers: Age of Ultron concept art posters on each day of the 2014 San Diego Comic-Con International which all combined together like "VUltron."
And here is the complete Avengers poster!
Links to all the individual poster reveals: Comic-Con 2014: Marvel Debuts IRON MAN, SCARLET WITCH and ULTRON Concept Art For AVENGERS 2
Comic-Con 2014: Marvel Debuts CAPTAIN AMERICA and BLACK WIDOW Concept Art For AVENGERS: AGE OF ULTRON
Comic-Con 2014: QUICKSILVER, VISION and HAWKEYE in Newest AVENGERS: AGE OF ULTRON Concept Art Posters
Comic-Con 2014: THOR and HULK Posters For AVENGERS: AGE OF ULTRON Revealed