I have overriden getHeaders()
as well. So far I haven't found a way to do that more easily.
See this example https://github.com/njzk2/VolleyTwitter/blob/master/src/com/njzk2/twitterbrowser/TokenRequest.java of an overriden Request to include the Authorization header.
From Volley code, I don't see any way of adding custom headers if not by overriding the Request object.
Moreover, I don't see how it can be easily added given the structure of Volley, as for the Images, ImageRequests are created by the ImageLoader.
If I were to modify Volley to allow this, I would make it possible to use a custom class extends ImageRequest in the ImageLoader. The anonymous ImageRequest class in ImageLoader makes it a bit complicated, though.