Hello, Lauren!
Thanks very much for your response. I appreciate you doing that. I knew I wasn't the only person having this issue! :)
Everything on my end appears to be set up correctly (canonical headers, dumped CDN cache, etc.), but my images still aren't being indexed. It's been well over a month.
I know for a fact that Google isn't indexing my CDN images because if I add an image from any other source, it gets indexed properly. I really have no idea. If you do happen to figure this out, please let me know. I will forever be grateful for that.