The display of the iPad measures 9.7 inch diagonally and packs 1024 x 768 pixels. You might think that a landscape wallpaper measuring 1024 x 768 will do, but you need to keep in mind that iPad can be used in both portrait and landscape orientations. That is why you require a wallpaper measuring 1024 x 1024. It shall be noted that both iPad and iPad 2 have same resolutions and same display sizes.
The wallpaper of your iPad tells a lot about your personality and thus you should have the appropriate wallpaper on your iPad. For example, if you loved the Transformer 3 movie and you are a dude, you would love to have Rosie Huntington iPad wallpaper on it. If you are a serious music listener, anything other than Selana Gomez iPad wallpaper would do, because we all know – she cannot sing.