Is that the scene you're referring to? If so, it looks fine. That's just one peice of the edge of the SSD- and the edge is super thin compared to the rest of the SSD. So that frigate isn't oversized.
Do you see how small the corvette is, next to the frigate? And the corvette is in front of the frigate. That's not the correct size ratio, as established both by shots in RotJ with the entire fleet at Sullust and also by ESB, where the Falcon appeared to be subjectively about the same size next to the frigate as the corvette in this shot.
Edit: in fact, I the corvette in this shot may actually be SMALLER in comparison with the frigate than the Falcon was in Empire.
Ah, yes, my mistake. Firstly, never noticed the corvette onscreen. Secondly, up till now, when I watched that clip, I thought the 'vette was behind the frigate
"So you want to live on a planet?"
"No. I think I'd find it a bit small and wierd."
"Aren't they dangerous? Don't they get hit by stuff?"
