Re-record the manual under the scene-referred pipeline

D19 changed how every raw photograph renders, so every picture was
stale; all forty are recorded again from this tree. Beside the ones
already in the page there is now one for Tone Mapping: an alpine frame
whose clouds sit near white, its White Point raised to bring them back
and lowered for a brighter picture, its Contrast raised, then Before.

The panorama film unticks the first frame and ticks it back, so the
Frames list and the re-solve show; it no longer films minutes of
"Reading the frames", cutting from the first seconds of the job to the
alignment. The manual's presets menu opens beside the rail, not beside
the photograph.

docs/manual/README.md

@@ -174,6 +174,8 @@ the strip at its head narrows it to one group.
 Exposure, contrast, highlights, shadows, blacks, whites and a tone curve.
 Hold `Before` to see the photograph as it was.
 
+![Raising exposure, pulling the highlights, lifting the shadows, then holding Before](media/develop-light.gif)
+
 `Tone Mapping`, last in the group, is how the scene is fitted onto the
 screen, and it runs after every other adjustment. `White Point` says how many
 stops above middle grey reach white — raise it to bring a bright sky back
@@ -181,9 +183,10 @@ from white, lower it for a brighter, punchier picture — and `Contrast` sets
 the slope of the curve between. Every adjustment above it works on the scene
 as the camera recorded it, highlights beyond white included, so pulling the
 highlights recovers what the sensor caught rather than what the screen could
-show.
+show. A JPEG has been fitted to a screen already, by the camera, so on a
+JPEG these two do nothing.
 
-![Raising exposure, pulling the highlights, lifting the shadows, then holding Before](media/develop-light.gif)
+![Raising the white point to bring the clouds back from white, lowering it for a brighter picture, raising the contrast, then holding Before](media/develop-tonemap.gif)
 
 ### Looking closer
 
@@ -299,7 +302,7 @@ a gradient over the sky whose `Print Exposure` burns it in.
 
 Every change is a step; `Undo` and the History panel walk them. `Snapshot`
 keeps the current state under a name. `Presets`, at the foot of the tool
-rail on the left, opens a menu of presets beside the photograph, filed in
+rail on the left, opens a menu of presets beside the rail, over the photograph, filed in
 folders that start closed: your own under `Yours`, then the ones DarkRoom
 ships — `Essentials`, `Skies`, and `Film`, which holds `Colour`, `Cinema`
 and `Black and white`, one measured stock each. Choosing a folder opens it;
@@ -356,7 +359,7 @@ It opens in develop all the same, on a reduced copy that is drawn from the
 full resolution wherever you zoom in, and it exports at full size. The same
 goes for a panorama Lightroom stitched and saved as a DNG.
 
-![Twelve frames aligned, the projections tried, and the border filled](media/panorama.gif)
+![Twelve frames aligned, the first left out and brought back, the projections tried, and the border filled](media/panorama.gif)
 
 ![The alignment on a cylinder, each frame outlined where it landed](media/panorama-aligned.png)