If you created imageview using xml file then follow the steps.
Solution 1:
Step 1: Create an XML file
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#cc8181"
>
<ImageView
android:id="@+id/image"
android:layout_width="50dip"
android:layout_height="fill_parent"
android:src="https://stackoverflow.com/questions/5089300/@drawable/icon"
android:layout_marginLeft="3dip"
android:scaleType="center"/>
</LinearLayout>
Step 2: create an Activity
ImageView img= (ImageView) findViewById(R.id.image);
img.setImageResource(R.drawable.my_image);
Solution 2:
If you created imageview from Java Class
ImageView img = new ImageView(this);
img.setImageResource(R.drawable.my_image);