Just a few points to add:
I don't think this is related to whether it's an old or new household.
I think the reason that people are noticing this when editing a household or moving sims, is simply because that's when the game is forced to generate new thumbnails for the household.
The game uses old thumbnails as long as the household doesn't change.
I'm also noticing that this starts happening when there are at least 5 adult sims in the household (haven't tested other household constellations so far). The zoom for 1-4 sims is still the same as it was before (I'm gonna call it zoom level 1). But as soon as the game changes to zoom level 2 with 5 or more sims, it now applies a larger zoom out than before.
I do think this is (indirectly) related to horses, but I don't think this is an intended feature, but more likely an oversight.
I can confirm that I tested households with 2, 3, 4, 5 & 6 sims and you seem to be correct. Everything is as it was before for households under 5 sims and the larger households all have this new zoom level. Hopefully if it was an oversight, it'll make it on the radar to get fixed. I'm going to hold off on gallery uploads for a while and see what happens because it will definitely trigger me if they're not all uniform down the road. 😳
I'm adding this new issue here as it's a similar concern regarding gallery images/thumbnails. The secondary pose is out of focus/alignment too but in different ways for our horses. The adults are pretty good but in my opinion need more work to get centered etc. It's the foals I'm mainly concerned about. All the foals are getting cut off in the second gallery image. They are way to far down towards the bottom of the frame. This thumbnail really needs work! Here is a sample. I'm not exactly sure how many second thumbnails for foals there are but I'm thinking they are all like this.
