Can anyone shed any light as to what may be going on here? 
I have two images. They are identical. The only difference is the domain name.
One image refuses to onebox on my Discourse running 3.3.0.beta2-dev (7a083daf27), the other image will onebox just fine with no issues.
Image one: https://dronescene.co.uk/images/uploads/temporiginal/test11.png
Image two: https://dev.dronescene.co.uk/images/uploads/temporiginal/test11.png
While scratching my head and trying to work out what the issue might be, I noticed the onebox url is appending a few extra parameters on the end of the URL:
I think this is a red herring though
If I view both images directly in a browser tab and look at the HTTP response headers in the network tab of the browser console, I can’t see any differences between the two.
There are no errors in my Discourse logs.
Might I have applied some domain-specific settings on my Discourse that I’ve long since forgotten about?
What else could cause the Onebox to throw a HTTP/404 when the image is actually there?
Where might I start in debugging why one url works and the other does not?
If relevant, both domains are proxied via Cloudflare - but all identical in the settings there too.
