<android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/toolbar_layout"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:fitsSystemWindows="true"
        app:layout_scrollFlags="scroll|exitUntilCollapsed">

        <android.support.v7.widget.Toolbar
            android:id="@+id/toolbar"
            android:layout_width="match_parent"
            android:layout_height="?attr/actionBarSize"
            app:layout_collapseMode="pin"
            app:popupTheme="@style/AppTheme.PopupOverlay" />

        <ImageView
            android:id="@+id/header_logo"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:scaleType="center"
            android:layout_gravity="center"
            app:layout_collapseMode="parallax"
            />

    </android.support.design.widget.CollapsingToolbarLayout>

ImageView im = (ImageView)findViewById(R.id.toolbar_layout);
im.setBitmap(image_here);

ImageView im = (ImageView)findViewById(R.id.toolbar_layout);
im.setBitmap(image_here);

ImageView im = (ImageView)findViewById(R.id.header_logo);
im.setBitmap(image_here);

ImageView ivHeader;
ivHeader = (ImageView)findViewById(R.id.header);

Picasso.with(this).load(data.getString("img_url")).into(ivHeader);

<android.support.design.widget.AppBarLayout
    android:id="@+id/flexible.appbar"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
    >

    <android.support.design.widget.CollapsingToolbarLayout
        android:id="@+id/flexible.collapsing"
        android:layout_width="match_parent"
        android:layout_height="300dp"
        app:title="@string/loading"
        app:expandedTitleMarginBottom="94dp"
        app:layout_scrollFlags="scroll|exitUntilCollapsed"
        app:expandedTitleTextAppearance="@style/CollapsingTextAppearance.Inverse"
        app:contentScrim="?colorPrimary">

        <ImageView
            android:id="@+id/header"
            android:layout_width="fill_parent"
            android:layout_height="match_parent"
            android:scaleType="centerCrop"
            android:src="@drawable/bg_navigation"
            android:tint="#BB3E50B4"
            tools:ignore="ContentDescription" />

        //.....

    </android.support.design.widget.CollapsingToolbarLayout>
</android.support.design.widget.AppBarLayout>