Show AI denoise in the manual on sharp, noisy frames

The ISO 8000 Brooklyn Bridge frame was soft at 1:1 before any denoising,
so it could not show that Best keeps detail. The section now shows five
sharp frames from ISO 4000 to 16000, each at 1:1 where hard edges meet
flat areas, Bilinear beside Best: a subway poster, a cathedral portal, a
circus clock, a clinic sign and graffiti. Fast is described, not shown.

at_develop opens a DNG when the name carries its extension. The scene
now fails when Best never lands instead of capturing the undenoised
frame twice.

docs/manual/README.md

@@ -236,13 +236,18 @@ already used is quick.
 `Strength` eases it off: below 100 % it puts back some of what was removed,
 as grain without colour, for a picture that does not look too smooth.
 
-The lamp and railing of a night frame at ISO 8000, at 1:1, by each method:
+Five sharp photographs at high ISO, each at 1:1 where hard edges meet
+flat areas, as the camera's ordinary conversion gives them and as `Best`
+develops them. The grain goes from the flat paper, stone, canvas and paint; the
+lines, the lettering and the carving keep their edges:
 
-| Bilinear | Fast |
-|---|---|
-| ![The railing and the lamp at ISO 8000, as the camera recorded them](media/develop-denoise-bilinear.png) | ![The same, with the Fast network](media/develop-denoise-fast.png) |
-| **Best** | |
-| ![The same, with the Best network](media/develop-denoise-best.png) | |
+| | Bilinear | Best |
+|---|---|---|
+| ISO 4000 | ![A subway poster's masthead at ISO 4000, at 1:1, as the camera recorded it](media/develop-denoise-poster-bilinear.png) | ![The same with Best](media/develop-denoise-poster-best.png) |
+| ISO 8000 | ![The carving round a cathedral door at ISO 8000, at 1:1, as the camera recorded it](media/develop-denoise-portal-bilinear.png) | ![The same with Best](media/develop-denoise-portal-best.png) |
+| ISO 12800 | ![A clock's numerals over a circus ring at ISO 12800, at 1:1, as the camera recorded it](media/develop-denoise-clock-bilinear.png) | ![The same with Best](media/develop-denoise-clock-best.png) |
+| ISO 16000 | ![Lettering on a white panel at ISO 16000, at 1:1, as the camera recorded it](media/develop-denoise-sign-bilinear.png) | ![The same with Best](media/develop-denoise-sign-best.png) |
+| ISO 16000 | ![Graffiti on a white wall at ISO 16000, at 1:1, as the camera recorded it](media/develop-denoise-graffiti-bilinear.png) | ![The same with Best](media/develop-denoise-graffiti-best.png) |
 
 It works on raw files from any camera with the usual colour pattern of
 red, green and blue squares — not on JPEGs, and not yet on Fujifilm's

docs/manual/index.html

@@ -315,11 +315,16 @@ or exported, does not wait a second time, and switching back to a method
 already used is quick.
 <code>Strength</code> eases it off: below 100 % it puts back some of what was removed,
 as grain without colour, for a picture that does not look too smooth.</p>
-<p>The lamp and railing of a night frame at ISO 8000, at 1:1, by each method:</p>
-<table><thead><tr><th>Bilinear</th><th>Fast</th></tr></thead><tbody>
-<tr><td><img src="media/develop-denoise-bilinear.png" alt="The railing and the lamp at ISO 8000, as the camera recorded them" /></td><td><img src="media/develop-denoise-fast.png" alt="The same, with the Fast network" /></td></tr>
-<tr><td><strong>Best</strong></td><td></td></tr>
-<tr><td><img src="media/develop-denoise-best.png" alt="The same, with the Best network" /></td><td></td></tr>
+<p>Five sharp photographs at high ISO, each at 1:1 where hard edges meet
+flat areas, as the camera's ordinary conversion gives them and as <code>Best</code>
+develops them. The grain goes from the flat paper, stone, canvas and paint; the
+lines, the lettering and the carving keep their edges:</p>
+<table><thead><tr><th></th><th>Bilinear</th><th>Best</th></tr></thead><tbody>
+<tr><td>ISO 4000</td><td><img src="media/develop-denoise-poster-bilinear.png" alt="A subway poster&#39;s masthead at ISO 4000, at 1:1, as the camera recorded it" /></td><td><img src="media/develop-denoise-poster-best.png" alt="The same with Best" /></td></tr>
+<tr><td>ISO 8000</td><td><img src="media/develop-denoise-portal-bilinear.png" alt="The carving round a cathedral door at ISO 8000, at 1:1, as the camera recorded it" /></td><td><img src="media/develop-denoise-portal-best.png" alt="The same with Best" /></td></tr>
+<tr><td>ISO 12800</td><td><img src="media/develop-denoise-clock-bilinear.png" alt="A clock&#39;s numerals over a circus ring at ISO 12800, at 1:1, as the camera recorded it" /></td><td><img src="media/develop-denoise-clock-best.png" alt="The same with Best" /></td></tr>
+<tr><td>ISO 16000</td><td><img src="media/develop-denoise-sign-bilinear.png" alt="Lettering on a white panel at ISO 16000, at 1:1, as the camera recorded it" /></td><td><img src="media/develop-denoise-sign-best.png" alt="The same with Best" /></td></tr>
+<tr><td>ISO 16000</td><td><img src="media/develop-denoise-graffiti-bilinear.png" alt="Graffiti on a white wall at ISO 16000, at 1:1, as the camera recorded it" /></td><td><img src="media/develop-denoise-graffiti-best.png" alt="The same with Best" /></td></tr>
 </tbody></table>
 <p>It works on raw files from any camera with the usual colour pattern of
 red, green and blue squares — not on JPEGs, and not yet on Fujifilm's