diff --git a/documentation/ref-manual/ref-variables.xml b/documentation/ref-manual/ref-variables.xml
index 1a3cedf98e..cf6885faf8 100644
--- a/documentation/ref-manual/ref-variables.xml
+++ b/documentation/ref-manual/ref-variables.xml
@@ -1726,7 +1726,42 @@ Core layer for images cannot be removed
 
         <glossentry id='var-IMAGE_FSTYPES'><glossterm>IMAGE_FSTYPES</glossterm>
             <glossdef>
-                <para>Formats of root filesystem images that you want to have created.</para>
+                <para>
+                    Specifes the format of the root filesystem create by
+                    the OpenEmbedded build system.
+                    Valid types include but are not limited to the following:
+                    <literallayout class='monospaced'>
+     jffs2
+     sum.jffs2
+     cramfs
+     ext2
+     ext2.gz
+     ext2.bz2
+     ext3
+     ext3.gz
+     ext2.lzma
+     btrfs
+     live
+     squashfs
+     squashfs-xz
+     ubi
+     ubifs
+     tar
+     tar.gz
+     tar.bz2
+     tar.xz
+     cpio
+     cpio.gz
+     cpio.xz
+     cpio.lzma
+     vmdk
+     elf
+                    </literallayout>
+                    For more information on how these types of images, see
+                    <filename>meta/classes/image_types*.bbclass</filename>
+                    in the
+                    <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+                </para>
             </glossdef>
         </glossentry>
 
@@ -1911,6 +1946,47 @@ Core layer for images cannot be removed
             </glossdef>
         </glossentry>
 
+        <glossentry id='var-IMAGE_TYPES'><glossterm>IMAGE_TYPES</glossterm>
+            <glossdef>
+                <para>
+                    Specifes the type of image created by the OpenEmbedded
+                    build system.
+                    Valid types include but are not limited to the following:
+                    <literallayout class='monospaced'>
+     jffs2
+     sum.jffs2
+     cramfs
+     ext2
+     ext2.gz
+     ext2.bz2
+     ext3
+     ext3.gz
+     ext2.lzma
+     btrfs
+     live
+     squashfs
+     squashfs-xz
+     ubi
+     ubifs
+     tar
+     tar.gz
+     tar.bz2
+     tar.xz
+     cpio
+     cpio.gz
+     cpio.xz
+     cpio.lzma
+     vmdk
+     elf
+                    </literallayout>
+                    For more information on how these types of images, see
+                    <filename>meta/classes/image_types*.bbclass</filename>
+                    in the
+                    <ulink url='&YOCTO_DOCS_DEV_URL;#source-directory'>Source Directory</ulink>.
+                </para>
+            </glossdef>
+        </glossentry>
+
         <glossentry id='var-INC_PR'><glossterm>INC_PR</glossterm>
             <glossdef>
                 <para>Helps define the recipe revision for recipes that share