Is there an application which let me crop a picture on my device into the correct size to use as wallpaper Do you know of software which can crop a photo or an image into the correct size to act as wallpaper ?

Now, if I download an image from the net  and try to use it as a wallpaper ( long pressing an image in a web browser, let's you use it as a wallpaper ), it always uses the top of the image. Depending on the picture, this makes a lot of pictures useless.

I could imagine a graphic application which let's met select a portion of an image ( the correct size for the device I'm running it on ), and than saves the cropped version and sets it as a wallpaper.

I am not so much interested into a graphic editing program on Android as such ( I will do graphic editing on the PC ), unless it gives me the option I am asking.

I am using an Archos 101 tablet running Froy 2.2.1 , if that should make a difference.
You can save the image to  SD Card and use the Gallery app to set the wallpaper. Gallery app has the feature to crop selected portion of an image and then save it as a wallpaper.