diff --git a/TeXmacs/progs/generic/document-menu.scm b/TeXmacs/progs/generic/document-menu.scm
index 083d8f703c..f18f4d8efd 100644
--- a/TeXmacs/progs/generic/document-menu.scm
+++ b/TeXmacs/progs/generic/document-menu.scm
@@ -936,6 +936,7 @@
  ("Palette" (interactive-background set-background '()))
  ("Pattern" (open-pattern-selector set-background "1cm"))
  ("Gradient" (open-gradient-selector set-background))
+ ("Picture" (open-background-picture-selector set-background))
  ("Other" (init-interactive-env "bg-color"))
 ) ;menu-bind
 
diff --git a/TeXmacs/progs/generic/pattern-selector.scm b/TeXmacs/progs/generic/pattern-selector.scm
index 7bef1c11e5..b2f83509a0 100644
--- a/TeXmacs/progs/generic/pattern-selector.scm
+++ b/TeXmacs/progs/generic/pattern-selector.scm
@@ -19,22 +19,41 @@
 ;; Name conversions
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
+(define (pattern-name->url s)
+  ;; 兼容旧版本写入的 /C/Users/... 路径。
+  (if (and (os-windows?)
+        (>= (string-length s) 3)
+        (== (string-ref s 0) #\/)
+        (char-alphabetic? (string-ref s 1))
+        (== (string-ref s 2) #\/)
+      ) ;and
+    (system->url (string-append (substring s 1 2) ":" (substring s 2 (string-length s)))
+    ) ;system->url
+    (unix->url s)
+  ) ;if
+) ;define
+
+(define (pattern-url->name u)
+  ;; 用正斜杠避免 Windows 反斜杠破坏偏好设置的 Scheme 语法。
+  (if (os-windows?) (string-replace (url->system u) "\\" "/") (url->unix u))
+) ;define
+
 (define (encode-pattern-name u)
   (let* ((name (if (string? u) u (url->unix u)))
          (t (url->unix (url-tail u)))
          (p (url->unix "$TEXMACS_PATH/misc/patterns"))
          (a (url->unix "$TEXMACS_PATH/misc"))
-         (p* (url-append (unix->url p) "dummy"))
-         (a* (url-append (unix->url a) "dummy"))
+         (p* (url-append (pattern-name->url p) "dummy"))
+         (a* (url-append (pattern-name->url a) "dummy"))
         ) ;
-    (cond ((string-starts? name p) (url->unix (url-delta p* (unix->url name))))
+    (cond ((string-starts? name p) (url->unix (url-delta p* (pattern-name->url name))))
           (else u)
     ) ;cond
   ) ;let*
 ) ;define
 
 (define (decode-pattern-name s)
-  (let* ((name (unix->url s))
+  (let* ((name (pattern-name->url s))
          (base1 "$TEXMACS_PATH/misc/patterns/neutral-pattern.png")
          (base2 "$TEXMACS_PATH/misc/pictures/gradients/vertical-white-black.png")
          (base (if global-gradient? base2 base1))
@@ -239,7 +258,12 @@
 ) ;define
 
 (define (normalize-color col)
-  (if (tm-func? col 'pattern) (apply tm-pattern (cdr col)) col)
+  ;; 图片选择器已经将本地路径规范化为可写入文档的 Unix 形式。
+  ;; 再经 tm-pattern 转为系统路径会在 Windows 偏好项中留下反斜杠。
+  (if (and (tm-func? col 'pattern) (not global-picture?))
+    (apply tm-pattern (cdr col))
+    col
+  ) ;if
 ) ;define
 
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
@@ -247,16 +271,16 @@
 ;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
 
 (tm-widget (pattern-name-selector)
-  (let* ((name (unix->url (get-name)))
+  (let* ((name (pattern-name->url (get-name)))
          (curr (decode-pattern-name (get-name)))
          (setter (lambda (c)
                    (when (and (pair? c) (url? (car c)))
-                     (set-name (url->unix (car c)))
+                     (set-name (pattern-url->name (car c)))
                    ) ;when
                  ) ;lambda
          ) ;setter
         ) ;
-    (hlist (enum (set-name (url->unix answer))
+    (hlist (enum (set-name (pattern-url->name answer))
              (list `(verbatim ,(url->system name)) "")
              `(verbatim ,(url->system name))
              "15em"
@@ -269,7 +293,7 @@
               (choose-file setter "Background pattern" "image" "" curr)
              ) ;
              (global-gradient? (choose-file setter "Background gradient" "image" "" curr))
-             ((url-rooted? (unix->url (get-name)))
+             ((url-rooted? (pattern-name->url (get-name)))
               (choose-file setter "Background picture" "image" "" curr)
              ) ;
              (else (choose-file setter "Background picture" "image"))
diff --git a/devel/2090.md b/devel/2090.md
index dcd3927a0c..cbfb12a005 100644
--- a/devel/2090.md
+++ b/devel/2090.md
@@ -99,3 +99,38 @@ tmu 格式下 pattern 第一个参数（图片链接）以 UTF-8 原样落盘
 
 ### 8.4 涉及文件
 - `TeXmacs/progs/generic/document-menu.scm`
+
+## 9 恢复文档背景图片入口（2026-08-12）
+
+### 做什么
+恢复“文档 -> 颜色 -> 背景色 -> 图片”菜单项。
+
+### 原因
+背景图片选择器仍可生成合法的三参数 `pattern`，但排查期间入口被临时隐藏，用户无法使用该功能。
+
+### 实现方式
+在 `document-background-color-menu` 中恢复已有的
+`open-background-picture-selector` 动作。
+
+### 涉及文件
+- `TeXmacs/progs/generic/document-menu.scm`
+
+## 10 修复 Windows 背景图片路径（2026-08-12）
+
+### 做什么
+使背景图片选择器在 Windows 下能够预览并应用本地图片。
+
+### 原因
+文件对话框返回的系统路径若直接写入偏好设置，会包含反斜杠并导致 Scheme 解析失败；
+而将其写为 `/C/...` 又无法被系统路径解析器识别为 Windows 盘符路径。
+
+### 实现方式
+选择器将 Windows 图片保存为 `C:/...`：该形式可由 `url_system` 识别，且只使用正斜杠，
+能够安全写入 Scheme 偏好设置。预览和正式渲染优先通过 `url_system` 解析，同时保留对旧版
+Unix 形式路径的回退。背景图片不再重复经过 `tm-pattern`，避免确认时再次生成反斜杠。
+
+### 涉及文件
+- `TeXmacs/progs/generic/pattern-selector.scm`
+- `src/Graphics/Renderer/brush.cpp`
+- `src/Typeset/Env/env_exec.cpp`
+- `tests/Graphics/Renderer/brush_test.cpp`
diff --git a/src/Graphics/Renderer/brush.cpp b/src/Graphics/Renderer/brush.cpp
index f413053faf..03cafc05e1 100644
--- a/src/Graphics/Renderer/brush.cpp
+++ b/src/Graphics/Renderer/brush.cpp
@@ -108,9 +108,15 @@ url
 brush_rep::get_pattern_url () {
   tree t= get_pattern ();
   if (is_atomic (t) || N (t) == 0 || !is_atomic (t[0])) return url ();
-  url u= url_system (as_string (t[0]));
+  string name= as_string (t[0]);
+  // 选择器保存的 C:/ 路径须经系统解析器识别为盘符路径。
+  url u= url_system (name);
   url r= resolve_pattern (u);
   if (!is_none (r)) return r;
+  // 保持对旧版 Unix 形式路径的兼容。
+  u= url_unix (name);
+  r= resolve_pattern (u);
+  if (!is_none (r)) return r;
 #if defined(KERNEL_L3)
   url base= url_pwd ();
 #else
diff --git a/src/Typeset/Env/env_exec.cpp b/src/Typeset/Env/env_exec.cpp
index 2b9a14ea78..917fa12d7f 100644
--- a/src/Typeset/Env/env_exec.cpp
+++ b/src/Typeset/Env/env_exec.cpp
@@ -2059,7 +2059,9 @@ tree
 edit_env_rep::exec_pattern (tree t) {
   if (N (t) < 1) return tree (ERROR, "bad pattern");
   if (no_patterns && N (t) == 4 && is_atomic (t[3])) return exec (t[3]);
-  url im= url_system (exec_string (t[0]));
+  string name= exec_string (t[0]);
+  // 选择器保存的 C:/ 路径须经系统解析器识别为盘符路径。
+  url im= url_system (name);
   url image;
   if (is_none (base_file_name)) {
     image= resolve_pattern (im);
@@ -2067,6 +2069,16 @@ edit_env_rep::exec_pattern (tree t) {
   else {
     image= resolve_pattern (relative (base_file_name, im));
   }
+  if (is_none (image)) {
+    // 保持对旧版 Unix 形式路径的兼容。
+    im= url_unix (name);
+    if (is_none (base_file_name)) {
+      image= resolve_pattern (im);
+    }
+    else {
+      image= resolve_pattern (relative (base_file_name, im));
+    }
+  }
   if (is_none (image)) return "white";
   int imw_pt, imh_pt;
   image_size (image, imw_pt, imh_pt);
diff --git a/tests/Graphics/Renderer/brush_test.cpp b/tests/Graphics/Renderer/brush_test.cpp
index f93bcb083b..4a8d3f3e7d 100644
--- a/tests/Graphics/Renderer/brush_test.cpp
+++ b/tests/Graphics/Renderer/brush_test.cpp
@@ -13,6 +13,7 @@
 
 #include "base.hpp"
 #include "brush.hpp"
+#include "tm_url.hpp"
 
 #include <QtTest/QtTest>
 #include <moebius/tree_label.hpp>
@@ -28,6 +29,7 @@ private slots:
   void test_atomic_color ();
   void test_pattern_three_args ();
   void test_pattern_four_args ();
+  void test_pattern_system_url ();
   void test_malformed_patterns ();
 };
 
@@ -50,6 +52,15 @@ TestBrush::test_pattern_four_args () {
   QCOMPARE (brush (p)->get_type (), brush_pattern);
 }
 
+void
+TestBrush::test_pattern_system_url () {
+#if defined(OS_MINGW) || defined(OS_WIN)
+  url picture= url_system ("C:/Users/test/Picture.png");
+  QCOMPARE (as_string (picture, URL_SYSTEM),
+            string ("C:\\Users\\test\\Picture.png"));
+#endif
+}
+
 void
 TestBrush::test_malformed_patterns () {
   // 缺宽度/高度参数：绘制时会读取 p[1]/p[2]，必须回退 no_brush