Minor edits to the Image Service overview section

Minor edits to the wording in the Image Service overview.

Change-Id: I2c3771955d1d2c5814e757929734d43594dcc1dc
Implements: blueprint installation-guide-improvements

doc/common/section_getstart_image.xml

@@ -3,6 +3,16 @@
     xmlns:xlink="http://www.w3.org/1999/xlink" version="5.0"
     xml:id="image-service-overview">
       <title>OpenStack Image Service</title>
+      <para>The OpenStack Image Service is central to infrastructure-as-a-service (IaaS)
+        as shown in <xref linkend="conceptual-architecture"/>. It accepts API requests
+        for disk or server images, and image metadata from end users or OpenStack Compute
+        components. It also supports the storage of disk or server images on various
+        repository types, including OpenStack Object Storage.
+        </para>
+      <para>A number of periodic processes run on the OpenStack Image Service to
+        support caching. Replication services ensures consistency and
+        availability through the cluster. Other periodic processes
+        include auditors, updaters, and reapers.</para>
       <para>The OpenStack Image Service includes the following
         components:</para>
       <variablelist>
@@ -35,13 +45,4 @@
            read-only usage.</para></listitem>
        </varlistentry>
       </variablelist>
-      <para>A number of periodic processes run on the OpenStack Image Service to
-        support caching. Replication services ensures consistency and
-        availability through the cluster. Other periodic processes
-        include auditors, updaters, and reapers.</para>
-      <para>The OpenStack Image Service is central to
-        infrastructure-as-a-service (IaaS) as shown in <xref
-        linkend="conceptual-architecture"/>. It accepts API requests for images
-        or image metadata from end users or OpenStack Compute components, and
-        can store its disk files in OpenStack Object Storage.</para>
     </section>