How to stretch only the middle of a GUI texture?

Our artist gave me a GUI texture with a small length.I want to stretch it for each scene.I try to change transform’s scale and pixel inset,but it’s not what I want it to be !I want to stretch the GUI texture only at it’s middle part.How to do it?

Use the GUITexture component’s border settings, in the inspector it shows leftBorder, rightBorder, topBorder, and bottomBorder, these specify how many pixels on each edge will be unstretched.