Utility of android nine patch

Question

I would like to know why do we use nine-patch ? I know is to shrink or stretch images but if I want to resize an image can\'t we just do it on a dedicated image editor like

Answer 1

Nine-patch is to do the stretching on the run time... If you use an Button with a custom background for example and say width-> fill_parent... there is a lot of different devices out there with different resolution how are you going to prepare images for all of them... you give a nine patch and its stretch on the run.