Image Element and API - Pass Bearer Token

[mr_rodge]

Hi, first post.

I've been tinkering with Jasper Studio CE for a few weeks, learning the 'ins and outs' of how to do reports (I'm a complete newbie to reporting).  I'm using ODK Central to gather data and I've managed to use its API with Studio to access the data.  It's clunky but it involves a data adapter with POST request to obtain a token and start a session, then this token being passed as a parameter to a subreport and used in a GET request to get the actual data.  This is all working fine and dandy.  The problem comes with the image element - I can construct a URL easily enough, but how do I pass the header containing the token?

Many thanks!