diff --git a/public/theme/boost/lang/en/theme_boost.php b/public/theme/boost/lang/en/theme_boost.php
index 432c34cc498..db911973e5f 100644
--- a/public/theme/boost/lang/en/theme_boost.php
+++ b/public/theme/boost/lang/en/theme_boost.php
@@ -25,6 +25,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 $string['advancedsettings'] = 'Advanced settings';
+$string['aigeneratedimage'] = 'AI generated image';
 $string['backgroundimage'] = 'Background image';
 $string['backgroundimage_desc'] = 'The image to display as a background of the site. The background image you upload here will override the background image in your theme preset files.';
 $string['brandcolor'] = 'Brand colour';
diff --git a/public/theme/boost/lib.php b/public/theme/boost/lib.php
index 1e08db56f6f..31bdb6a5d93 100644
--- a/public/theme/boost/lib.php
+++ b/public/theme/boost/lib.php
@@ -58,19 +58,36 @@ function theme_boost_get_extra_scss($theme) {
     // Sets the login background image.
     $loginbackgroundimageurl = $theme->setting_file_url('loginbackgroundimage', 'loginbackgroundimage');
     $backgroundposition = '';
-    if (empty($loginbackgroundimageurl)) {
+    $isdefaultloginimage = empty($loginbackgroundimageurl);
+    if ($isdefaultloginimage) {
         // Use the default login background image.
         $loginbackgroundimageurl = $theme->image_url(
             'login_background',
             'theme',
         );
-        // Set the default background position to ensure the watermark is visible.
-        $backgroundposition = 'background-position: bottom right;';
+        // Set the default background position to center.
+        $backgroundposition = 'background-position: center;';
     }
     $content .= 'body.pagelayout-login #page .login-layout-left { ';
-    $content .= "background-image: url('$loginbackgroundimageurl'); background-size: cover; {$backgroundposition}";
+    $content .= "background-image: url('$loginbackgroundimageurl'); ";
+    $content .= "background-size: cover; {$backgroundposition} position: relative;";
     $content .= ' }';
 
+    // Add a watermark to indicate the image is AI generated, but only for the default image.
+    if ($isdefaultloginimage) {
+        $content .= 'body.pagelayout-login #page .login-layout-left::after {';
+        // Escape the label for use in a CSS string value: collapse newlines (which would break the CSS string)
+        // and escape single quotes and backslashes via addcslashes.
+        $ailabel = preg_replace('/[\r\n]+/', ' ', get_string('aigeneratedimage', 'theme_boost'));
+        $content .= " content: '" . addcslashes($ailabel, "'\\") . "';";
+        $content .= ' position: absolute; bottom: 1rem; right: 1rem;';
+        $content .= ' color: $white;';
+        $content .= ' font-size: 0.8rem;';
+        $content .= ' text-shadow: 0 1px 2px $black;';
+        $content .= ' pointer-events: none;';
+        $content .= ' }';
+    }
+
     // Always return the background image with the scss when we have it.
     return !empty($theme->settings->scss) ? "{$theme->settings->scss}  \n  {$content}" : $content;
 }
diff --git a/public/theme/boost/pix/login_background.jpg b/public/theme/boost/pix/login_background.jpg
index 4bb0cb99d8f..d4173697c35 100644
Binary files a/public/theme/boost/pix/login_background.jpg and b/public/theme/boost/pix/login_background.jpg differ
diff --git a/public/theme/boost/scss/moodle/login.scss b/public/theme/boost/scss/moodle/login.scss
index 364b1524442..aba66193bc9 100644
--- a/public/theme/boost/scss/moodle/login.scss
+++ b/public/theme/boost/scss/moodle/login.scss
@@ -1,7 +1,7 @@
 $login-layout-left-bg: $primary !default;
 $login-layout-panel-padding: 3rem !default;
 $login-layout-content-width: 576px !default;
-$login-layout-copy-width: 360px !default;
+$login-layout-copy-width: 450px !default;
 $login-input-bg: $gray-100 !default;
 
 .pagelayout-login {
@@ -34,6 +34,7 @@ $login-input-bg: $gray-100 !default;
 .login-layout-left-content {
     max-width: $login-layout-copy-width;
     text-align: center;
+    text-shadow: 1px 1px 3px $black;
 }
 
 .login-layout-stats {
diff --git a/public/theme/boost/style/moodle.css b/public/theme/boost/style/moodle.css
index bdbcdcf5e84..d513903f188 100644
--- a/public/theme/boost/style/moodle.css
+++ b/public/theme/boost/style/moodle.css
@@ -35599,8 +35599,9 @@ textarea[data-auto-rows] {
 }
 
 .login-layout-left-content {
-  max-width: 360px;
+  max-width: 450px;
   text-align: center;
+  text-shadow: 1px 1px 3px #000000;
 }
 
 .login-layout-stats {
diff --git a/public/theme/classic/lang/en/theme_classic.php b/public/theme/classic/lang/en/theme_classic.php
index 2ed2627014b..3767244b0ac 100644
--- a/public/theme/classic/lang/en/theme_classic.php
+++ b/public/theme/classic/lang/en/theme_classic.php
@@ -26,6 +26,7 @@
 defined('MOODLE_INTERNAL') || die();
 
 // Raw SCSS setting.
+$string['aigeneratedimage'] = 'AI generated image';
 $string['choosereadme'] = 'Classic is a highly-customisable theme, based on Boost, with an alternative navigation layout. This theme is intended to be used directly, or as a parent theme when creating or updating custom themes to utilise Bootstrap 4.';
 $string['configtitle'] = 'Classic';
 $string['navbardark'] = 'Use a dark style navbar';
diff --git a/public/theme/classic/lib.php b/public/theme/classic/lib.php
index bdac2e137f8..5e4c8d21e9a 100644
--- a/public/theme/classic/lib.php
+++ b/public/theme/classic/lib.php
@@ -109,19 +109,36 @@ function theme_classic_get_extra_scss($theme) {
     // Sets the login background image.
     $loginbackgroundimageurl = $theme->setting_file_url('loginbackgroundimage', 'loginbackgroundimage');
     $backgroundposition = '';
-    if (empty($loginbackgroundimageurl)) {
+    $isdefaultloginimage = empty($loginbackgroundimageurl);
+    if ($isdefaultloginimage) {
         // Use the default login background image.
         $loginbackgroundimageurl = $theme->image_url(
             'login_background',
             'theme',
         );
-        // Set the default background position to ensure the watermark is visible.
-        $backgroundposition = 'background-position: bottom right;';
+        // Set the default background position to center.
+        $backgroundposition = 'background-position: center;';
     }
     $content .= 'body.pagelayout-login #page .login-layout-left { ';
-    $content .= "background-image: url('$loginbackgroundimageurl'); background-size: cover; {$backgroundposition}";
+    $content .= "background-image: url('$loginbackgroundimageurl'); ";
+    $content .= "background-size: cover; {$backgroundposition} position: relative;";
     $content .= ' }';
 
+    // Add a watermark to indicate the image is AI generated, but only for the default image.
+    if ($isdefaultloginimage) {
+        $content .= 'body.pagelayout-login #page .login-layout-left::after {';
+        // Escape the label for use in a CSS string value: collapse newlines (which would break
+        // the CSS string) and escape single quotes and backslashes via addcslashes.
+        $ailabel = preg_replace('/[\r\n]+/', ' ', get_string('aigeneratedimage', 'theme_classic'));
+        $content .= " content: '" . addcslashes($ailabel, "'\\") . "';";
+        $content .= ' position: absolute; bottom: 1rem; right: 1rem;';
+        $content .= ' color: $white;';
+        $content .= ' font-size: 0.8rem;';
+        $content .= ' text-shadow: 0 1px 2px $black;';
+        $content .= ' pointer-events: none;';
+        $content .= ' }';
+    }
+
     if (!empty($theme->settings->navbardark)) {
         $content .= file_get_contents($CFG->dirroot .
             '/theme/classic/scss/classic/navbar-dark.scss');
diff --git a/public/theme/classic/pix/login_background.jpg b/public/theme/classic/pix/login_background.jpg
index 4bb0cb99d8f..d4173697c35 100644
Binary files a/public/theme/classic/pix/login_background.jpg and b/public/theme/classic/pix/login_background.jpg differ
diff --git a/public/theme/classic/style/moodle.css b/public/theme/classic/style/moodle.css
index a6d0d639f23..c03c364c311 100644
--- a/public/theme/classic/style/moodle.css
+++ b/public/theme/classic/style/moodle.css
@@ -35599,8 +35599,9 @@ textarea[data-auto-rows] {
 }
 
 .login-layout-left-content {
-  max-width: 360px;
+  max-width: 450px;
   text-align: center;
+  text-shadow: 1px 1px 3px #000;
 }
 
 .login-layout-stats {