Pro Sites – thickbox.js loading an insecure GIF

I’m auditing a new installation with Pro Sites and the Blogs MU theme. I’m getting an insecure URL notice on the /pro-sites/ payment page with the Stripe payment module.

I traced this back. The cause is thickbox.js loading a GIF using the http:// protocol. This appears to be an issue hard coded into thickbox.js or their implementation of the jQuery imgLoader library.

Is it possible to wp_dequeue_script() thickbox.js on the /pro-site/ page?