Well, if you are using href than the reference to the image will be external to Aware IM and you will have to worry about providing the image with your software.
The root directory for external resources such as images in Aware IM is AwareIM/Tomcat/webapps/AwareIM. So if you put an image into this directory you can refer to it as: <img src="myimage.jpg" ... >
You can also create a sub-folder under this directory and refer to the image like this:
<img src="myfolder/myimage.jpg" ... >
