That picture is on my blog from Bazookajoe here on the forums. Yessss, the Victrix are massive , especially the riders.
You can see more comparisons here:
https://destroycarthage.blogspot.com/2018/10/victrix-made-shetland-pony-for.htmlThey're also quite wide, and I find that their Greek, Gallic, Iberian and Romans all follow a similar pattern. To be far, they are well done minis for the details and one cannot deny that they would be a pleasure to paint.

However, they seem a bit on the large size when next to anything else... including Victrix' on cavalrymen!

That's a HUGE rider!

And next to the pachyderm it seems the horses could well be near cousins. I guess the old forest elephant may not have been so big, but it just seems odd...
From my understanding on it, ancient horses in this part of the world were often described as shorter and stocky compared to medieval counterparts. There were larger horses in times of old, and it seems the Romans had some standards and preference for large, handsome horses - but what was available in just the Mediterranean world before expansion would have been limited, and I am sure that selective breeding and eventually more trading with the east would soon develop bigger, stronger breeds of horses.
Ultimately, I think though its really the riders that there's an issue with for me personally. That Numidian VS Roman.. is ludicrous!
I think Victrix did well with their Numidians. Strabos describes Numidian horses as "Small, hardy animals" which is the feeling I get from their cavalry. I think Victrix got the description right for the Numidian cavalry so I always recommend them for use in Carthage and Rome.
The Victrix cavalry are all gone in my collection now. I sold them off or traded them, since the size of their riders and horses simply bothered me way too much. Now I use Aventine and Foundry miniatures, which feel a bit closer to what I imagine horse size would be.