Here is a guide on how to get images and set them to your opening iPod Touch Wallpaper.
Owning Your iPod Touch
Making your new iPod Touch truly yours is the mission of every new owner. To do this you stuff it full of media and applications that highlight your own preferences, but you really need to color is just right. You can do this by setting an opening wallpaper image that comes up when you first hit the Home button on your inactive iPod Touch. This will bring up an image before you unlock the iPod Touch and it is the first thing you will see for every use. You do not just have to choose from a series of stock images for your iPod Touch wallpaper. Instead you have a fully customizable option in the same fashion as many of the other iPod Touch Settings.
Saving Pictures on Your iPod Touch
The first thing you have to do is to get the image that you want for your wallpaper onto your iPod Touch. You can do this through iPod Touch and iPhone wallpaper applications, but this is still pretty limiting. You can take your own picture and then upload it onto your computer, then sync it to your iPod Touch as you would with any file. Then you can put it into your Saved Photos folder. You can also save an image from the internet in Safari. You simply do this by pressing down on the image and then selecting to do so. Another way to do this is to take a screenshot of what is on your iPod Touch currently. You do this by pressing the power and Home buttons at the same time, which will cause a white flash to occur and then the image will be saved. Make sure that everything on the screen displayed is what you want there.
iPod Touch Wallpaper
Once you have the pictures you want go to the iPod Touch Settings Option. Go to the top of the second block and select General, which is rigth above Music. In the iPod Touch General Settings go to the top of the second section and select Wallpaper, which is right above Sounds. When you are in here you have two options: Wallpaper and Saved Photos. You can browse through the stock iPod Touch Wallpaper photos, or the ones you saved. Find the picture you want and press it. When the Wallpaper Preview comes up simply hit the Set Wallpaper button. It will then drop away and that picture will be saved as your iPod Touch Wallpaper.