What happened to Thumbnails?

[MIPS]

I noticed it changed a few months ago.
Normally when someone attaches an image to a post (rather than using IMG tags and an external host) you get a little thumbnail you can click on to see the full image. The thumbnail is small, but you can still see what the image is. If you aren't signed in however you just get a list at the bottom of the post of the attachments and a little icon to the left of each indicating it's an image, but no actual thumbnail of the image (it's a bandwidth saving thing)

Well now I roam through threads while signed in and I don't see thumbnails. Someone attaches an image you gotta click each attachment to view them.
I understand vBulletin 3.8.4 is very, very old but what changed in the back-end?

Edited: for example, here's posts with attached images from the beginning of the year. Note how there is an image.

https://videokarma.org/showthread.php?t=275481

A few months later...

https://videokarma.org/showthread.php?t=275790