I've been making it a habit to upload the extracted login backgrounds to the wiki whenever they come out (unless the devs upload them as a wallpaper on their Weibo or their official sites), they'll be added to any of the respective T-dolls Alt Gallery section if people wanna upload them here.

Majority of the CG's used on the wiki is as close to the source asset file (which is why all the T-dolls CG's are 1024x1024), one of the ways you can tell its an image directly extracted from the game, is by its resolution, all the login backgrounds have a width of 2048x, as well as a height of 2048x, however i crop out the black spaces in the image which they use just as a filler (Ever wondered why there is those black spaces on the login screen when you have the screen at a certain resolution?)