images in pod

I have just started using pod, and really love it so far. Based on the comments in one of the releases, it seems like I should be able to create a placeholder for an image in my .odt template, and then load it from the file system when I populate my template using the renderer. Specifically, the 0.3.0 release on Pypi states "new function 'document' that allows to integrate, in a pod template, the content of an external document or image." I cannot find any documentation that explains how this is done. Can someone help me out? Thanks!