Bug overview description.
When uploading images from a URL with the newer Twitter URL format, such as
https://pbs.twimg.com/media/EP7d6_qU0AEtNoF?format=jpg&name=orig
the upload page does not show the image. So far, all Twitter image URLs using the newer format that I've tried don't show anything on the upload page. The images do upload correctly and I can see it on the new post, just not on the upload page. Also, if I put the image URL directly into a new browser tab, it shows there just fine.

Relatedly, the same images given in the older URL format:
https://pbs.twimg.com/media/EP7d6_qU0AEtNoF.jpg:orig
do show up in the upload page just fine. All other direct upload sources I've tried -- FA, Pixiv, and FN off the top of my head -- also show just fine. It's just the new Twitter image URL format that doesn't show.

My browser is Pale Moon 28.8.2.1. It was happening with prior versions as well.

What part(s) of the site page(s) are affected?
The upload form page.

What is the expected behavior?
The image being uploaded is shown on the right hand side of the page.

What actual behavior is given instead?
The image is not shown on the upload page.

Time of incident (if applicable).
Feb. 5th 2020, approx 4pm PST was the latest for me as of this report, though it's been happening for the past several days ever since I started using the new Twitter URL format (it's likely been an issue for quite a bit longer, I just didn't use the new format to notice it).

Can you reproduce the bug every time?
Yes.

What steps did you take to replicate this bug?
1. Go to upload a new image.
2. Paste in a Twitter image URL to upload with the new format, such as:
https://pbs.twimg.com/media/EP7d6_qU0AEtNoF?format=jpg&name=orig

Errors or other messages returned (if any).
No error messages or other noticeable anomalies. The image just doesn't show.