How to Add Background in Settings and all Dark Background

GUIDE:

1. Decompile framework-res.apk
2. Go to res/value/style.xml
3. Find
<item name="colorBackground">@color/background_dark </item>
Change
<item name="colorBackground">@color/transparent </item>
And
<item name="windowBackground">@drawable/screen_background_dark </item>
Change
<item name="windowBackground">@drawable/yourimage</item>

4. Find
<style name="Theme.Black" parent="@style/Theme">
Find
<item name="colorBackground">@color/black </item>
Change
<item name="colorBackground">@color/transparent </item>
Find
<item name="windowBackground">@color/black </item>
Change
<item name="windowBackground">@drawable/yourimage </item>
for Image Size 5" -> 720 x 1024"
How to know your screensize image.. just create screenshot then details.. get your width and height thats it 

Place your image in drawable-hdpi or drawable-xhdpi (it depends on your phone)
Compile it