for anybody looking to change all background images use APK editor studio, it will show all the files you need to change on the right hand side.
From there just right click, open resource and swap out with your file. Make sure all names are the same, ex ic_launcher and ic_launcher_forgeground. Do this for all of them and make sure you change to correct sizes as I had trouble with the app crashing if it wasn't correct.
With the icon i had trouble, I changed it in two places, all are located within "res.drawable"
I am just struggling with the dns as I cant find this, maybe its because the app I am using is already rebranded?
install APK Easy Tool to decompile the apk. It will generate a folder with all the apk files, there you will find the file com/nathnetwork/xciptv/LoginActivity to change the dns.