Either that add-on is only changing the size at display time, or isn’t working for the images in your sample, as they’re about 6x wider than 1080. 
I have no experience with the following tool, but it looks like it could do the job - you could specify a maximum size and tell it not to resize images that are already smaller. Please back up your media folder and experiment on a subsection of it - if you end up making unwanted changes you should be able to restore from the backup you created. I recommend you close Anki or temporarily disable the periodic media sync in the preferences until you’re happy with things.
Reverting to an older toolkit version in the next update is an option, but I’d like to get a better feel for how widespread this issue is first - because it sounds like aside from this issue, display of smaller images has actually improved a bit since the previous update.