Inserting Dynamic Pictures from File Server in rtf

hi , I want to display images on report from rtf template , i.e bi-publisher in obiee , how should this achieve?  I followed

bellow solution

1. use the concat function to build the URL string. For example:

url:{concat(SERVER,'/',IMAGE_DIR,'/',IMAGE_FILE)}

where SERVER, IMAGE_DIR, and IMAGE_FILE are element names from the XML file that hold the values to construct the URL.

but it does not work. so please suggest any solution.