Proper Wallpaper Size Is Not Exactly 1024 x 1024 px
But an image that size will actually be shrunk by the iPad to fit inside the area under the black bar that shows time, battery and wifi strength.
It's subtle, but the software shrinking changes the image -- one of my images looks noticeably less sharp after it's altered that way on the iPad.
That black bar is probably something like 10px or so, making the actual, proper size of wallpaper something closer to 1014px square.
Does anyone know the size of that black bar, or some way to determine it?
Mac Pro (early 2008) 2.8 GHz Quad-Core, Mac OS X (10.5.7)