Replace the default WinPE wallpaper image in the boot image or mounted WIM
Edit `winpeshl.ini` to launch a custom shell or startup script
Modify `startnet.cmd` to...
Replace `WinPE.jpg` in the WinPE media source folder
Keep the same filename: `WinPE.jpg`
Keep the same image format and dimensions if required by your WinPE build
Copy...