Toolbar image centered

Toolbar is just a ViewGroup, you can customize is as much as you want.

Try this :

<android.support.v7.widget.Toolbar
   style="@style/ToolBarStyle"
   xmlns:android="http://schemas.android.com/apk/res/android"
   android:layout_width="match_parent"
   android:layout_height="wrap_content"
   android:background="?attr/colorPrimary"
   android:minHeight="@dimen/abc_action_bar_default_height_material">

    <ImageView
        android:layout_width="wrap_content"
        android:contentDescription="@string/logo"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:src="https://stackoverflow.com/questions/27534343/@drawable/ic_launcher"/>

 </android.support.v7.widget.Toolbar>

This should bring your imageView in center of toolbar.