North American electronics retailer Best Buy has added three previously unreleased screenshots to their GTA IV product page.
If Rockstar's release of exclusive retailer-only Grand Theft Auto: San Andreas wallpapers in 2004 were of any indication, then there is a chance that other major retailers (Wal-Mart, EB Games, GAME, etc.) will also be posting GTA IV exclusives of their own in the days to come. (Keep an eye on their respective websites just in case we miss it!)
We're still in the process of trying to obtain full sized versions of these latest images, so for now the low-res versions will have to suffice. Cheers!
Related Link: Topic at GTAForums