Unable to find file sources while loading an image

I make my own theme copying the reindeer theme on the /WebContent/VAADIN/themes/testtheme

It reeds the providen CSS, but when i made the same request that i have exposed before, I’ll get the same

java.lang.NullPointerException
	com.vaadin.terminal.ClassResource.<init>(ClassResource.java:75)
	com.example.test.DivisorComponentes.<init>(DivisorComponentes.java:29)
	com.example.test.TestApplication.init(TestApplication.java:14)
	com.vaadin.Application.start(Application.java:545)
	com.vaadin.terminal.gwt.server.AbstractApplicationServlet.startApplication(AbstractApplicationServlet.java:1008)
	com.vaadin.terminal.gwt.server.AbstractApplicationServlet.service(AbstractApplicationServlet.java:418)
	javax.servlet.http.HttpServlet.service(HttpServlet.java:717)

The DivisorComponentes class is the one that makes the call to the image loader.

        Embedded logo = new Embedded("logo-aviones", new ClassResource("../img/aviones.jpg", getApplication()  ));
        logo.setType(Embedded.TYPE_IMAGE); 

I’ve tried putting as path “/” , “…/” and whitout the slash …and i’ll get the same error.

Thanks in advance!
11132.jpg