They are, i specifically use a resize tool and set the maximum to these two values, maintaining the proportions ofc, so usually there's one value in that limit and the other inferior, even so i used to cut the original img so there's little background as possible and the girl ocuppy the most of the img, noticed that is not the ideal either, giving it a little berth makes the img more presentable in game, still is a proccess of "experimenting" and learning with how to craft a better img pack.All the images you add must have a size of 512x800 to avoid looking weird in the game.
I'm also trying to test how the game responds to a wide range of lewd (z) in the same cathegory, like if a casual (cas) outfit reach z3 (underwear). My theory is that the game can still assign it in public if they are certain conditions met, but will be a rare appearance, and at worst when they are supposed to undress to their underwear that casual outfit may appear, that i do not dislike, cuz the actual lewdness of the outfit is quite there, but there are also underwear img to choose from, so it should also be rare in that instance. The last img pack have a really wide range of lewdness in the outfits so i can test it in game, but gonna take a while.