Pixel dimensions for iPad wallpaper

I want to set a background wallpaper for my iPad that won't be cropped or otherwise distorted to fit the screen. In the past all that was required was to pad an image to the appropriate proportions in photoshop, but when I created an image to be precisely the pixel dimensions of the iPad3 screen, 2048x1536, attempts to set it as wallpaper still resulted in the the wallpaper settings blowing it up.

Is there any pixel size at which the bug-ridden iOS7 will not attempt to blow it up, ruining the image?

Or is there a set degree of enlargement it uses, like forcing everything to be double, that I can use to pad an image so the forced crop results in the final image being correct?

I'm really tired of the seeing my wrecked images every time I wake the iPad. And no, I have no interest whatsoever in Apple's screenshots.