They're obviously pixelated because they've been blow up lol.

Obviously they got hold of images meant for print media, provided by Sony themselves. No plot thickening there. All promo images for any game out there would be provided in the same blown up scale to meet the demands of print. They are not meant to be viewed this size on computer screens, but printed in smaller size and thus appearing as they would in the actual game, in 1080p.

I've always said that this game is no graphical masterpiece, but it's obvious that when you increase size from the original, all the lack in graphics etc., it's gonna be much more notorious, especially when it's looked zoomed in, like in a smaller screen. It's gonna happen with any game... maybe except Crysis.

It's really unfair because the game is not gonna be that resolution.

Yes, although devkits are commonly configured to render at several times the target resolution.  Forza 2 screen shots, for example, were sometimes released at 2560x1440. 

http://farm3.static.flickr.com/2094/2185266011_618d9970ac_b.jpg

That shot almost takes up the screen.(And thats not including any boardering or layouts.) The screen shot they are showing is about 4 times bigger(After reducing it by 50%). I doubt Sony would release screen shots for computer viewing that you would need to scroll at least 8 pages worth

Those files are suitable for print resolutions: set the image output to 600ppi and you'll have an 8.3x4.7 in image. Print the image on a quality printer and it will look extremely detailed.

Set the files for viewing at either 1920x1080 or 1280x720 (native render resolution) and again, the images look extremely detailed.

Everyone does realize that if you look at any image close enough, you can begin to see the limitations of detail of any source. Even any kid with a magnifying glass who ever looked at a printed image in a magazine or newspaper knows this.

Rest assured that if they took original 1280x720 screenshots and sized them up to 5000 pixels wide, they would look far worse than the shots they have. Just try saving one of them, and resize it down to 1280x720 and then back up again. It looks like crap.

This is an interesting point -- the images could be used for printing.  However, you don't need to do 600ppi for larger images.  300ppi is more than sufficient.  Heck, for very large images (>=20 inches wide) you can stretch to 200ppi because the viewer won't be nearly as close as if they were looking at a small image. 

it still looks good to me though i think that its a zoomed in pic

I sincerely doubt that Insomniac would make R2's graphics that bad. I do believe that they will be (at the very least, just a bit under) the stunning graphics that we saw on the other, smaller images.