When I say “new topic”, I mean directly on Discourse, not via API.
Originally, it’s a topic created from WP-Discourse; so should be this code:
For example, if you look at the first edit of the topic linked above, You see well the system replacing the images. So, WP-Discourse is likely not an issue.
Later, the original author updated the Wordpress post, the Discourse topic got updated and the original images are back:
Then a category change happened, and from there PullGotlinkedImages does nothing:
If you want the code used for the category change, it’s something like that: