How to create a custom button?

[jbjbjbborisb]

Hi there!
I would like to change the looks of a button. I already created an image (ninepatch) in Gimp and added it to my Unity project.

But how can I create a Ninepatch-Texture from that image to theme my button?
The Unity documentation gives no results on this topic. Also Google does not provide any useful search results

Thanks!

[Mikeysee]

Click the texture, in inspector open the sprite editor, change the border: