i know this works on LinearLayout, but i'm not sure it works on imageviews , worth a try ,you could do something like this on the background
so your imageview would look something like this maybe
<ImageView android:background="@drawable/rounded"/>
if you call this file rounded.xml or something
<?xml version="1.0" encoding="UTF-8"?>
<shape xmlns:android="http://schemas.android.com/apk/res/android"
android:shape="rectangle" >
<corners android:bottomRightRadius="10dp" android:bottomLeftRadius="10dp"
android:topLeftRadius="10dp" android:topRightRadius="10dp"/>
<stroke
android:color="@drawable/black"
android:width="1dp"
/>
</shape>
this page is a good reference http://developer.android.com/guide/topics/resources/drawable-resource.html