Rewrote documentation for web image optimization

docs/configuration.md

@@ -57,13 +57,7 @@ This part of the configuration concerns anything that can affect the whole site.
     - `tertiary`: hover states and visited [[graph view|graph]] nodes
     - `highlight`: internal link background, highlighted text, [[syntax highlighting|highlighted lines of code]]
     - `textHighlight`: markdown highlighted text background
-- `optimizeImages`: whether to optimize images for web serving when building Quartz. If this is set to `true`:
+- `optimizeImages`: whether to optimize images for web serving when building Quartz. Consider turning it off in local testing to speed up build time. See [[Images]] for more information.
-
-  - JPEG and PNG images will be stripped all metadata and converted to WebP format, and associated image links in [[wikilinks]] will be updated with the new file extension.
-  - A resized preview image will replace every local image that have custom dimensions defined either in their [wikilink](https://help.obsidian.md/syntax#External+images) or <img> tag. The original image (optimized or not) will still be assessable as a link on the preview image.
-
-  ![[images/engelbart.jpeg | 200]]<br/>
-  _An example optimized preview image of [Douglas Engelbart](https://awards.acm.org/award_winners/engelbart_5078811). Clicking on it opens an originally sized optimized image._
 
 ## Plugins
 

docs/plugins/Assets.md

@@ -4,7 +4,7 @@ tags:
   - plugin/emitter
 ---
 
-This plugin emits all non-Markdown static assets in your content folder (like images, videos, HTML, etc). The plugin respects the `ignorePatterns` and `optimizeImages` in the global [[configuration]].
+This plugin emits all non-Markdown static assets in your content folder (like images, videos, HTML, etc). The plugin respects the `ignorePatterns` and `optimizeImages` configurations in [[configuration#General-Configuration|General Configuration]].
 
 Note that all static assets will then be accessible through its path on your generated site, i.e: `host.me/path/to/static.pdf`
 

docs/plugins/CustomOgImages.md

@@ -64,6 +64,8 @@ The following properties can be used to customize your link previews:
 
 The `socialImage` property should contain a link to an image either relative to `quartz/static`, or a full URL. If you have a folder for all your images in `quartz/static/my-images`, an example for `socialImage` could be `"my-images/cover.png"`. Alternatively, you can use a fully qualified URL like `"https://example.com/cover.png"`.
 
+The `socialImage` link respects the `optimizeImages` configuration in [[configuration#General-Configuration|General Configuration]] and is automatically rewritten if web image optimization is turned on.
+
 > [!info] Info
 >
 > The priority for what image will be used for the cover image looks like the following: `frontmatter property > generated image (if enabled) > default image`.

docs/plugins/Images.md

@@ -0,0 +1,68 @@
+---
+title: Images
+tags:
+  - plugin/transformer
+---
+
+> [!note]
+> For information on how to add, remove or configure plugins, see the [[configuration#Plugins|Configuration]] page.
+
+> [!warning]
+> Removing this plugin is _not_ recommended. Use [[configuration#General-Configuration|General Configuration]] to turn web image optimization on or off.
+
+This plugin parses and rewrites HTML image tags to support image related features. It's currently associated with the following features:
+
+## Web Image Optimization
+
+When `optimizeImages` in [[configuration#General-Configuration|General Configuration]] is set to `true`:
+
+- JPEG and PNG images will be stripped all metadata and converted to WebP format, and associated image links in [[wikilinks]] will be updated with the new file extension.
+
+- A resized preview image will replace every local image that have custom dimensions defined either in their [wikilink](https://help.obsidian.md/syntax#External+images) or <img> tag. The original image (optimized or not) will still be assessable as a link on the preview image.
+
+<!-- prettier-ignore-start -->
+> [!note]+ Example usage
+>
+> The following markdown:
+>
+> ```md
+> ![[images/engelbart.jpeg | 200]]<br/>
+> _An example optimized preview image of [Douglas Engelbart](https://awards.acm.org/award_winners/engelbart_5078811). Clicking on it opens an originally sized optimized image._
+> ```
+>
+> generates the following HTML:
+>
+> ![[images/engelbart.jpeg | 200]]<br/>
+> _An example optimized preview image of [Douglas Engelbart](https://awards.acm.org/award_winners/engelbart_5078811). Clicking on it opens an originally sized optimized image._
+<!-- prettier-ignore-end -->
+
+If an image has custom dimensions set, this plugin registers corresponding preview image spec with the [[Assets]] emitter so that the latter generates an additional preview image that matches the aspect ratio but with a small resolution bump. Note that [[Assets]] never upscales an image, so preview image file sizes are never larger than the originally sized optimized images.
+
+Update the [[Assets]] emitter source code if you want to tweak the image format conversion or/and resizing logic. Here are a few things you could do:
+
+- Make image optimization emit [AVIF](https://caniuse.com/avif) images instead, which is considered a mainstream successor to the [WebP](https://caniuse.com/webp) format, has better compression ratio and image feature sets (such as HDR support), but currently has narrower browser support and may be slower in image processing.
+
+- Enable optimization for animated GIF / GIFV images. Note that animated image processing can be very slow, only use it after testing!
+
+> [!warning]
+> If you use image tags with custom dimensions directly in your markdown documents, remember to manually add a `data-slug` property with the [[paths | full slug]] of the image file, otherwise the [[Assets]] emitter won't know which file path to emit the preview image to.
+>
+> An example supported image tag with custom dimensions:
+>
+> ```html
+> <img href="../../assets/abc.jpg" width="100" data-slug="assets/abc.jpg" />
+> ```
+
+The logic to use optimized images in [[CustomOgImages | Custom OG Images]] is separately implemented in the `ogImage` emitter, but is fully transparent to end users.
+
+## Configuration options
+
+This plugin accepts the following configuration options:
+
+- `openLinksInNewTab`: (Dependent on [[Images#web-image-optimization|Web Image Optimization]]) If `true`, clicking on a preview image opens the originally sized optimized image in a new tab. Defaults to `false`.
+
+## API
+
+- Category: Transformer
+- Function name: `Plugin.Images()`.
+- Source: [`quartz/plugins/transformers/images.ts`](https://github.com/jackyzha0/quartz/blob/v4/quartz/plugins/transformers/images.ts).