Just Google it, but only if you want even more proof that anime was a mistake.
...but seriously, what happened here? Did they just forget they were drawing literally GIANTS for a moment, and it's just a continuity error? Or did the Macross folks literally make a file-sized Minmay poster that just happens to have absolutely no lettering or logos or anything that would make it LOOK like a poster? I mean, yeah, they could also have just gotten a giant-sized reproduction made after returning to their fleet, but that seems like it would be hard to get away with on several levels. Also, episode 25 is getting closer and closer, so my brain is defaulting to "somebody screwed up" as the default answer for everything right now.