That comparison would only make sense if compressed images were considered derivative works. They're not - copyright doesn't protect bytes on a disk, it protects creative expressions. Lossy compression doesn't affect the creative expression, so in copyright terms a compressed JPG is just a copy, and is covered exactly like the original image.

In contrast a derivative work is one creative expression that contains elements of another - like when you take an image and add commentary, or draw your own addition onto it, etc. And I'm pointing out that a trained model is not that - it's not itself a copyrightable expressive work. (We could think of it as a kind of algorithm for generating works, but algorithms aren't copyrightable.)