fix(snippets): save_baked_image writes the requested format

Image.save_render() takes its format from the scene's render.image_settings;
image.file_format is ignored. save_baked_image(..., "OPEN_EXR") therefore wrote
a PNG with an .exr name, the common case for precision normal maps.

The snippet now sets scene.render.image_settings.file_format for the call,
passes scene= to save_render, and restores the previous format in a finally.
The bake-high-to-low skill's save step says the same and shows the pattern.

Proof (local, .scratch/blender-4.5.11-windows-x64 and blender-5.2.1, magic
bytes of the written file, float Non-Color 8x8 image):
PNG -> PNG, JPEG -> JPEG, OPEN_EXR -> OPEN_EXR on both; image.source stays
GENERATED; scene format restored. Old pattern (img.file_format = "OPEN_EXR";
save_render) -> PNG on both.

Closes #332

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

Author: TMHSDigital

skills/bake-high-to-low/SKILL.md

@@ -114,11 +114,18 @@ Snippet: `snippets/bake_normal_high_to_low.py`.
 
 ### 5. Save the datablock
 
-The bake writes the image **in memory**. `Image.save()` on a `GENERATED` image flips `source` to `'FILE'` and drops the buffer — the trap `examples/image-pixels-testcard/` witnesses. Use `save_render()`:
+The bake writes the image **in memory**. `Image.save()` on a `GENERATED` image flips `source` to `'FILE'` and drops the buffer — the trap `examples/image-pixels-testcard/` witnesses. Use `save_render()`.
+
+`save_render()` writes in the format of the **scene's** `render.image_settings`, not `img.file_format`: setting `img.file_format = "OPEN_EXR"` and calling `save_render` still writes a PNG on a default scene. Set the scene's format for the call and restore it:
 
 ```python
-img.file_format = "PNG"
-img.save_render(filepath)
+settings = scene.render.image_settings
+previous = settings.file_format
+settings.file_format = "OPEN_EXR"  # or "PNG"
+try:
+    img.save_render(filepath, scene=scene)
+finally:
+    settings.file_format = previous
 ```
 
 Snippet: `snippets/save_baked_image.py`. Folded save is the wrong size: the trap is its own contract.

snippets/save_baked_image.py

@@ -1,7 +1,12 @@
 # Write a baked image datablock to disk without dropping the buffer.
 # Image.save() on a GENERATED image flips source to FILE and the pixels
 # re-source from disk — empty if the file was not the bake. save_render()
-# writes the same PNG and leaves source GENERATED.
+# writes the buffer and leaves source GENERATED.
+#
+# save_render() takes its format from the scene's render.image_settings, not
+# from image.file_format: setting image.file_format = "OPEN_EXR" alone still
+# writes the scene's format (a PNG by default). Set the scene's settings for
+# the call and restore them after.
 #
 # Reference:
 #   https://docs.blender.org/api/current/bpy.types.Image.html#bpy.types.Image.save_render
@@ -10,7 +15,13 @@
 import bpy
 
 
-def save_baked_image(image, filepath, file_format="PNG"):
-    image.file_format = file_format
-    image.save_render(filepath)
+def save_baked_image(image, filepath, file_format="PNG", scene=None):
+    scene = scene or bpy.context.scene
+    settings = scene.render.image_settings
+    previous = settings.file_format
+    settings.file_format = file_format
+    try:
+        image.save_render(filepath, scene=scene)
+    finally:
+        settings.file_format = previous
     return filepath