How to set background image for button in Android?

I Imported one image inside the drawable-mdpi, then implemented the image from button, but an error occurs no resource found here. How do I fix this issue?

I tried this:

main.xml

  <Button
        android:id="@+id/imageButtonSelector"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:background="@drawable-mdpi/button_focused_orange"/>