(Q)how to add wallpaper to LGLockScreenSettings.apk?

btw, anyone here that know how to add custom locksreen wallpaper to LGLockScreenSettings.apk? i have tried dwcompile the apk. and place the file into res/drawable-xxxhdpi and then compiled it back to apk. sign it. place back into system app. but the wallpaper still not showing up. maybe i should add some line to the xml file. but i dont know which one to edit. any help would be appreciate
Thanks


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