Not true at all. Copyright also applies to images and other forms of artistic work. Copyright almost certainly expends not only to images already provided in-game, but to any models that were substantively altered from base (the base model would remain copyright the original creator, the derivative work would be copyright the dev based on his license to use the original work).
do games work as a "artistic work" ? (is serious wondering)
yes i know about the in theory "copyright" that gets auto apply when people create stuff but in practice it sadly works different from what i have seen
if say just for as a example: the original model creator dislike how much hate he has gotten due to something saddoggames have done then the original creator of the model "base model" can remove saddoggames right to use his copyrighted model with then saddoggames can not really do anything then redo all the scenes in the game with does models so even if in theory saddoggames have copyright to the "looks" the model currently has in practice that is pretty much worthless if saddoggames lose the right to use the original model or the "base model"
you only need to look to some fan made mods or even movies to see how copyright works in practice because many of them has been copyright strikes to death by the original copyright holder despise the "artistic work" does fans did do when they made the mod or movie
heck i think even the story my has too many common tropes to be copyrighted in practice because it exist people who has sued someone ales just because they story is too similar to works that the person who made the claim but they lost due to the fact that just because the story my or not be similar or some character looks similar is not enough to go on for suing for copyright claim so in the end based from what i know and read about copyright in practice any "copyright" saddoggames has is pretty much worthless but sure i too wish that copyright works almost the same as in theory
but i end on is one thing that i said in the text you qoute of me " but then in the end i don't knows every copyright laws in the world "