diff --git a/inc/customizer.php b/inc/customizer.php
index 979c0a6..b1d742d 100644
--- a/inc/customizer.php
+++ b/inc/customizer.php
@@ -27,7 +27,7 @@ function radiate_customize_register( $wp_customize ) {
  * Binds JS handlers to make Theme Customizer preview reload changes asynchronously.
  */
 function radiate_customize_preview_js() {
-	wp_enqueue_script( 'radiate_customizer', get_template_directory_uri() . '/js/customizer.js', array( 'customize-preview' ), '20130508', true );
+	wp_enqueue_script( 'radiate_customizer', get_template_directory_uri() . '/js/customizer.js', array( 'customize-preview' ), wp_get_theme( get_template() )->get( 'Version' ), true );
 }
 
 add_action( 'customize_preview_init', 'radiate_customize_preview_js' );
diff --git a/js/customizer.js b/js/customizer.js
index a83540d..50e45c5 100644
--- a/js/customizer.js
+++ b/js/customizer.js
@@ -33,4 +33,23 @@
 			}
 		} );
 	} );
+
+	// Custom background: core rewrites the theme's background style element, but the theme paints #content.
+	function radiateUpdateBackground() {
+		var image = wp.customize( 'background_image' )();
+
+		$( '#content' ).css( {
+			'background-color'     : wp.customize( 'background_color' )() || '',
+			'background-image'     : image ? 'url("' + image + '")' : 'none',
+			'background-repeat'    : wp.customize( 'background_repeat' )(),
+			'background-position'  : 'top ' + wp.customize( 'background_position_x' )(),
+			'background-attachment': wp.customize( 'background_attachment' )()
+		} );
+	}
+
+	$.each( [ 'color', 'image', 'repeat', 'position_x', 'attachment' ], function ( i, prop ) {
+		wp.customize( 'background_' + prop, function ( value ) {
+			value.bind( radiateUpdateBackground );
+		} );
+	} );
 } )( jQuery );
diff --git a/tests/e2e/specs/customizer/background-image-preview.spec.ts b/tests/e2e/specs/customizer/background-image-preview.spec.ts
new file mode 100644
index 0000000..35c3b38
--- /dev/null
+++ b/tests/e2e/specs/customizer/background-image-preview.spec.ts
@@ -0,0 +1,40 @@
+import { test, expect } from "../../fixtures";
+import { ADMIN_STATE, hasAdminCredentials } from "../../utils/login";
+
+test.use({ storageState: ADMIN_STATE });
+
+/**
+ * @area customizer
+ * @tier fresh
+ * @guards radiate-pro#48
+ * @source fix/48-background-image-preview 2026-09-29; js/customizer.js
+ * @why WordPress live-previews the background settings by rewriting the theme's
+ *      background style element, but Radiate paints its background on #content,
+ *      so choosing an image changed nothing in the Customizer preview until
+ *      publishing. The image is only previewed, never saved. Guards image and
+ *      repeat; position, attachment and colour share the same handler and are
+ *      deliberately not asserted separately.
+ */
+test("the Customizer previews a background image and its repeat setting live @fresh @customizer", async ({
+  page,
+}) => {
+  test.skip(!hasAdminCredentials(), "needs TGQA_ADMIN_USER / TGQA_ADMIN_PASS");
+  test.setTimeout(120_000);
+  page.on("dialog", (dialog) => dialog.accept());
+  await page.goto("/wp-admin/customize.php");
+  await expect(page.locator("#customize-theme-controls")).toBeVisible({ timeout: 90_000 });
+
+  const preview = page.frameLocator("#customize-preview iframe").last();
+  const content = preview.locator("#content");
+  await expect(content).toBeVisible({ timeout: 60_000 });
+
+  // Any URL works: only the computed style is read, the file need not load.
+  await page.evaluate(() => {
+    const api = (window as any).wp.customize;
+    api("background_image").set(`${api.settings.url.home}/wp-content/themes/radiate/screenshot.png`);
+    api("background_repeat").set("no-repeat");
+  });
+
+  await expect(content).toHaveCSS("background-image", /radiate\/screenshot\.png/);
+  await expect(content).toHaveCSS("background-repeat", "no-repeat");
+});