android weird memory issue with my app

I'm new to Android. My app's memory usage increased 10 MB when I add
<ImageView android:layout_width="wrap_content" android:layout_height="match_parent" android:src="@drawable/icon"/> to my main activity's xml file. the drawable is a 64x64 png icon which only takes 4kb space on my hard drive. it seems all other icons in my app are using 100-1000 times of their actual sizes in memory. Why is that and How can I solve this? I'm using Nexus 5 emulator with api level 17