```kotlin
import android.os.Bundle
import android.widget.ImageView
import androidx.appcompat.app.AppCompatActivity
class MainActivity : AppCompatActivity() {
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val imageView: ImageView = findViewById(R.id.imageView)
imageView.setImageResource(R.drawable.background_image)
}
}
```
Output:
The code provided sets a background image from the assets folder in an ImageView in an Android app using Kotlin.