diff --git a/doc/image-guide/ch_creating_images_manually.xml b/doc/image-guide/ch_creating_images_manually.xml
index 99dc142e8f..c9d331e484 100644
--- a/doc/image-guide/ch_creating_images_manually.xml
+++ b/doc/image-guide/ch_creating_images_manually.xml
@@ -80,6 +80,12 @@ default              active     yes</computeroutput></screen>
             </mediaobject>You will be shown a series of dialog boxes
             that will allow you to specify information about the
             virtual machine.</para>
+            <note><para>
+            When using qcow2 format images you should check the option
+            'customize before install', go to disk properties and
+            explicitly select the qcow2 format. The ensures the virtual
+            machine disk size will be correct.
+            </para></note>
     </section>
     <section xml:id="virt-install">
         <title>Use virt-install and connect by using a local VNC