Grabbing Query Strings in an AWS Authorizer

I currently have an AWS custom authorizer set up for my API gateway on Lambda. It works with my client side app and I am able to authorize properly, except for when I call a link (a link to the api gateway) in an img tag. From my understanding one cannot change the Authorization header the img tag sends out, so I thought I would append the authorization token to the link itself. The link looks something like this:

http://ift.tt/2fFzs2X

How would I allow the custom authorizer to retrieve that token? I understand there's a query string field in method request, but that seems to only deliver data to the underlying lambda.

Another solution could also work here too.