Scale Images in Different Resolutions XML

Question

I have created 4 resolution folders and put the appropriate image sizes into each as seen in the picture below:

I have also created 8 different layout folders for various screen sizes as seen in the picture below:

As you can see in the picture below, I need to re-size the images in each according XML file so they fill the screen:

I use this code to scale down images which works fine:

android:adjustViewBounds="true"  
    android:maxWidth="150dp" 
    android:scaleType="fitCenter"

But I cannot figure out how to scale up images. I have been trying to use this code:

android:adjustViewBounds="true"  
    android:minWidth="150dp" 
    android:scaleType="fitCenter"

Any ideas on how to scale up the images? Thank you!!

XML:

    <ImageButton
    android:id="@+id/btnPlay"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_centerHorizontal="true"
    android:layout_below="@+id/imageView1"
    android:layout_marginTop="15dp"
    android:background="@null"
    android:src="@drawable/btn_play"
    android:adjustViewBounds="true"  
    android:scaleX="1.5"
    android:scaleY="1.5"
    android:scaleType="fitXY"  />

Answer 1

Have you tried?:

android:scaleX="1.5" // 1 is 100% size
android:scaleY="1.5"