Vaderisnothayden said:
Dark Horse's comics series takes place before ANH, so it doesn't account for the difference between ANH and ROTJ Jabbas.

I probably haven't read it in ten years, and don't remember anything placing it pre-ANH, but if that's where licensing has placed it, so it goes.

And Jabba was a lot more than just different in size. They gave him an appearance that totally changed his personality, from sinister and clever to silly and cutesy. It wasn't just a bad special effect. A special effect that doesn't work is presumably at least intended to work, but with Jabba there was clearly no intention of making it consistent with the ROTJ Jabba, so the scene screams out contempt for what had been previously established in the films and thus for the old films as a whole.

There's nothing silly or cutesy about his appearance--at least, no sillier than he was in RotJ. It's simply a slightly different appearance, due to the limitations placed upon and inherent to the CGI artists of the time. Perhaps your impression of his personality is based more on his mood than his appearance? Like all creditors and collection agencies, he is relatively friendly the first time he calls to collect--but he means business, and will freeze you in carbonate (or do worse to your credit score) if you don't pay up.