Added alt text for images based on editorial feedback.

xml/vm_security.xml

@@ -128,6 +128,8 @@ You can run AMD SEV-SNP protected virtual machines using the &libvirt; framework
 <imageobject role="fo">
 <imagedata fileref="vm_security_create_vm.png" width="75%"/>
 </imageobject>
+<textobject role="description"><phrase>Select Customize configuration before install</phrase>
+</textobject>
 <imageobject role="html">
 <imagedata fileref="vm_security_create_vm.png" width="75%"/>
 </imageobject>
@@ -144,6 +146,8 @@ You can run AMD SEV-SNP protected virtual machines using the &libvirt; framework
 <imageobject role="fo">
 <imagedata fileref="vm_security_create_vm_xml.png" width="75%"/>
 </imageobject>
+<textobject role="description"><phrase>Click XML tab</phrase>
+</textobject>
 <imageobject role="html">
 <imagedata fileref="vm_security_create_vm_xml.png" width="75%"/>
 </imageobject>
@@ -159,6 +163,8 @@ To protect the virtual machine with AMD SEV-SNP, set the correct firmware by mod
     <imageobject role="fo">
     <imagedata fileref="vm_security_xml_os.png" width="75%"/>
     </imageobject>
+    <textobject role="description"><phrase>Set firmware</phrase>
+    </textobject>
     <imageobject role="html">
     <imagedata fileref="vm_security_xml_os.png" width="75%"/>
     </imageobject>
@@ -173,6 +179,8 @@ To protect the virtual machine with AMD SEV-SNP, set the correct firmware by mod
         <imageobject role="fo">
         <imagedata fileref="vm_security_xml_launchsecurity.png" width="75%"/>
         </imageobject>
+        <textobject role="description"><phrase>Add launchSecurity</phrase>
+    </textobject>
         <imageobject role="html">
         <imagedata fileref="vm_security_xml_launchsecurity.png" width="75%"/>
         </imageobject>
@@ -183,13 +191,15 @@ To protect the virtual machine with AMD SEV-SNP, set the correct firmware by mod
 <para>Click <guilabel>Apply</guilabel> and then click the <guilabel>Details</guilabel> tab.</para>
 </step>
 <step>
-<para>Select CPUs in the left-hand list and set the CPU type to <literal>host-model</literal>:</para>
+<para>Select CPUs in the left-hand list and set the CPU <guilabel>Model</guilabel> to <literal>host-model</literal>:</para>
 <figure>
 <title>The <guimenu>Details</guimenu> view of virtual machine configuration</title>
 <mediaobject>
 <imageobject role="fo">
 <imagedata fileref="vm_security_create_vm_details.png" width="75%"/>
 </imageobject>
+<textobject role="description"><phrase>Select CPU model</phrase>
+</textobject>
 <imageobject role="html">
 <imagedata fileref="vm_security_create_vm_details.png" width="75%"/>
 </imageobject>