To set an image to fill 50% of the screen on all Android devices, what size of image should I keep in a resource folder?

get the screen size of device and set the image height screenheight/2

get height by this code

1. DisplayMetrics displayMetrics = new DisplayMetrics(); 
2. getWindowManager().getDefaultDisplay().getMetrics(displayMetrics); 
3. int height = displayMetrics.heightPixels; 
4. int width = displayMetrics.widthPixels; 

or do something like this in xml code

2. android:orientation="vertical" 
3. android:layout_width="match_parent" 
4. android:layout_height="match_parent"> 
6. android:layout_width="match_parent" 
7. android:layout_height="0dp" 
8. android:layout_weight="0.5" 
9. android:background="#ff0000" 
10. > 
12. android:layout_width="match_parent" 
13. android:layout_height="match_parent" 
14. android:src="@drawable/your_image" 
15. android:adjustViewBounds="true" 
16. /> 
17.  
19. android:layout_width="match_parent" 
20. android:layout_height="0dp" 
21. android:layout_weight="0.5" 
22. android:background="#00ff00" 
23. /> 
24.