Illustrator un-intentionally scaling .pngs?

Hoping someone has an answer, I have been searching for days with no resolution.



I use illustrator to create backgrounds for games. I have been using the "Save for web and devices" to export as 24 bit pngs. for the most part thsi works but there is always some little thing or 10 that has to be adjusted then re- exported. The backgrounds contain all vector elements and I have tried with fairly good accuracy to use align to pixel grid and then even verify most assets are on whole pixels to include strokes. Text is generally outlined, and I trim the entire thing to my artboard when exporting.



So the background loaded in photoshop "looks" ok, but it didn't work. Here is the specific: the Background is 1024x768 24 bit .png all looks well in photoshop, but when we began lining up the buttons and such we noticed a problem. In trying to find the error I took the .png and "placed" it back into the Illustrator file using the place command (mind you the exact .png I just exported from .ai) I positioned it at 0,0 using the transform palette (and my art board is zeroed out to the rulers as well) and it does not match the illustrator layers. I am not saying it's blurry I understand "raster happens" I am saying everything is shifted slightly. When I look at the transform palette the placed image reads as 1023.872 x 767.904 so I assume that scaling it back up to 1024x768 would fix it, but it does not.



So why does illustrator place the image at a different size, and how can I get a raster image out of illustrator that stays true. I have tired all of the anti-aliasing options in the image size tab of save for web, all give different results but all still get scaled when placing them back into Illustrator.



Thanks,



LVC