docs(screenshots): document automated screenshot workflow

- explain screenshot generation, platform scope, and build requirements
- replace platform tabs with a single Windows interface screenshot
- remove obsolete macOS and Linux screenshot references
- clarify screenshot metadata and manual-only entries

3 files changed, 35 insertions, 24 deletions

diff --git a/scripts/screenshots/screenshots.yaml b/scripts/screenshots/screenshots.yaml
index 5ac7865..5b8f632 100644
--- a/scripts/screenshots/screenshots.yaml
+++ b/scripts/screenshots/screenshots.yaml
@@ -24,7 +24,7 @@ global_sources:
 entries:
   - id: main-window
     doc: src/content/docs/guides/understand-interface.mdx
-    ref: img-1  # the "Windows" tab of the window tour
+    ref: img-1  # the window tour at the top of the page
     scenario: main-window
     size: 1280x960
     sources:
@@ -550,15 +550,7 @@ entries:
     highlight: key_group
     sources: [src/ui/main_window/, src/ui/widgets/]
 
-  # Made by hand: other operating systems and their own windows.
-  - id: interface-macos
-    doc: src/content/docs/guides/understand-interface.mdx
-    ref: img-2
-    status: manual-only
-  - id: interface-linux
-    doc: src/content/docs/guides/understand-interface.mdx
-    ref: img-3
-    status: manual-only
+  # Made by hand: windows the screenshot mode cannot render.
   - id: windows-signature
     doc: src/content/docs/appendix/code-binary-verify.md
     ref: img-1
diff --git a/src/content/docs/appendix/contribute.md b/src/content/docs/appendix/contribute.md
index e2bf5a4..3d5daf2 100644
--- a/src/content/docs/appendix/contribute.md
+++ b/src/content/docs/appendix/contribute.md
@@ -295,6 +295,28 @@ to add the header to files that have none.
 The old `.devcontainer/` setup was removed. Set up your environment with the
 steps above instead.
 
+## Manual Screenshots
+
+The screenshots in this manual are made automatically, not by hand.
+GpgFrontend has a hidden screenshot mode that opens each window in a fixed
+state, with demo keys, a fixed clock and the same fonts every time. The
+scripts in the Manual repository's `scripts/screenshots/` folder start that
+mode, take each picture, upload it and put the new link into the page. Its
+`README.md` explains how to run them.
+
+- **Windows only:** every screenshot is taken on Windows 11, in English, with
+  the light theme. The manual shows only these, so there is one set to keep up
+  to date. macOS and Linux look a little different, but the windows and
+  buttons are the same.
+- **Build option:** the scripts need a binary configured with
+  `-DGPGFRONTEND_BUILD_SCREENSHOT_MODE=ON`. It cannot be combined with
+  `GPGFRONTEND_BUILD_STABLE`.
+- **Where the scenes live:** each window state is a scenario in
+  `src/screenshot/`, and the demo data is in `resource/screenshot/`.
+- **Changes are noticed:** each screenshot lists the source files it depends
+  on. When you change one of them, the next run marks that screenshot as out
+  of date and takes it again.
+
 ## Make Your Changes
 
 Development happens on `main`, and releases are tagged from it. The
diff --git a/src/content/docs/guides/understand-interface.mdx b/src/content/docs/guides/understand-interface.mdx
index 184deb0..75e3cd7 100644
--- a/src/content/docs/guides/understand-interface.mdx
+++ b/src/content/docs/guides/understand-interface.mdx
@@ -5,7 +5,7 @@ sidebar:
   order: 2
 ---
 
-import { Aside, Tabs, TabItem } from "@astrojs/starlight/components";
+import { Aside } from "@astrojs/starlight/components";
 
 This page gives you a tour of the GpgFrontend window, so you can find your way
 around and do your tasks with ease.
@@ -14,17 +14,16 @@ When GpgFrontend starts, a small **Starting GpgFrontend** window may appear
 first. It shows a progress bar and a line that says what is being loaded, such
 as your key databases or modules. The main window opens when it is done.
 
-<Tabs>
-  <TabItem label="Windows">
-    ![][img-1]
-  </TabItem>
-  <TabItem label="macOS">
-    ![][img-2]
-  </TabItem>
-  <TabItem label="Linux">
-    ![][img-3]
-  </TabItem>
-</Tabs>
+![The GpgFrontend main window][img-1]
+
+<Aside type="note" title="About the screenshots">
+
+The screenshots in this manual are made automatically from the current version
+of GpgFrontend, so they stay up to date. They are all taken on Windows. On
+macOS and Linux the window looks a little different, but the parts, buttons,
+and menus are the same.
+
+</Aside>
 
 ## The Window at a Glance
 
@@ -373,8 +372,6 @@ you are working with. Click any of them for more details.
   [Portable Mode](/advanced/portable-mode/).
 
 [img-1]: https://image.cdn.bktus.com/i/2026/10/25/6b49ddb4975940fa55474104cc0d64cad7f7833e-0.webp
-[img-2]: https://image.cdn.bktus.com/i/2026/06/29/d4edebb69dfc39c8bb7115cc8a6da00cecef096d.webp
-[img-3]: https://image.cdn.bktus.com/i/2026/08/20/f22625f6783706979e8e78fda0b261d7ee30de46.webp
 [img-4]: https://image.cdn.bktus.com/i/2026/10/25/001e0f26a7c53b45674daac4d2d59e0a009b03be-0.webp
 [img-5]: https://image.cdn.bktus.com/i/2026/10/25/67f6100c6318706c38629e9100d7ea3413a1ddee-0.webp
 [img-6]: https://image.cdn.bktus.com/i/2026/10/25/4fe7757dc97c824295a6046d1753160f4d157c42-0.webp