Bundle files inside executable Jar

Hello.!

I have created a simple JFrame with an image background in Sikuli IDE 1.3.

My script is called test.sikuli and it is inside a folder called "test".

The image I use for background is inside the folder "test".

My problem is when I export to jar runnable from Sikuli IDE, the image background for the JFrame is not bundle inside the Jar.

I even add the background image to the folder where sikuli api is but still not bundle inside the Jar.

Can you give me an example of how I bundle this image inside the jar.?

thanks..!