Oh man, I get a similar problem.
I put on value the complete path of my image(that is .jpg) but nothing displays.
If you known something, put here.
Check the location of your page. If you are in /pages/MyPage.xhtml and you want to render someting with a relative path, you need to calculate from the root. So you use a / to indicate the root or use ../ meaning one directory up, or ./ which means actual dir. If you have a fixed image location Always try to refer from it from root of your application, meaning /images/myImage.gif