I have googled it.
So that's a downgrade? Wow. So they went and downgraded a pre-rendered cutscene... interesting. Absolutely pointless, but interesting.
LOL. The fact is, the assets are exactly the same but in different lighting conditions. That's it. They aren't even running in real time on a PS3 any way. They are rendered on a farm of 8 PS3's in higher resolution. Why would they downgrade it if the PS3 doesn't have to even render it? That's because they didn't.
The last E3 build pic doesn't make sense. Seems like it was altered. Look at Drake's desert outfit... it looks like it's from another scene. Though I won't lose my time looking into that.