Struct ImageOptimizationPlugin 

pub struct ImageOptimizationPlugin {
    pub quality: u8,
    pub avif_quality: u8,
    pub lazy_avif: bool,
    pub breakpoints: Vec<u32>,
}

Plugin that optimises images and rewrites HTML with <picture> tags.

Runs in after_compile:

1. Scans site_dir for JPEG/PNG images
2. Generates WebP and AVIF variants at responsive widths
3. Rewrites <img> tags to <picture> with srcset
4. Adds loading="lazy", decoding="async", width, height

The quality and breakpoints are configurable via the struct fields.

Fields

quality: u8

WebP encoding quality (1–100). Defaults to 80.

avif_quality: u8

AVIF encoding quality (1–100). Defaults to 70 — see the DEFAULT_AVIF_QUALITY private constant for the rationale.

lazy_avif: bool

Skip AVIF encoding for non-priority images (saves build time at the cost of bandwidth on modern browsers). Hero images marked fetchpriority="high" always get AVIF regardless — see issue #521 AC5.

Currently exposed as a config knob; per-image priority data is only known to the HTML rewriter (which preserves fetchpriority="high" and loading="eager"), so the present implementation always encodes AVIF for every responsive variant of every collected image. Honoured-by-default in a follow-up once priority metadata is plumbed from the shortcode layer into collect_images.

breakpoints: Vec<u32>

Responsive width breakpoints in pixels. Defaults to [320, 640, 1024, 1440].

Trait Implementations

impl Clone for ImageOptimizationPlugin

fn clone(&self) -> ImageOptimizationPlugin

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for ImageOptimizationPlugin

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for ImageOptimizationPlugin

Available on crate feature image-optimization only.

fn default() -> Self

Returns the “default value” for a type.

impl Plugin for ImageOptimizationPlugin

Available on crate feature image-optimization only.

fn name(&self) -> &'static str

Returns the unique name of this plugin.

fn after_compile(&self, ctx: &PluginContext) -> Result<(), SsgError>

Called after site compilation completes.

fn before_compile(&self, _ctx: &PluginContext) -> Result<(), SsgError>

Called before site compilation begins.

fn transform_html( &self, html: &str, _path: &Path, _ctx: &PluginContext, ) -> Result<String, SsgError>

Per-file HTML transform hook — called once per HTML file during the fused transform pass.

fn has_transform(&self) -> bool

Returns true if this plugin implements transform_html. Override to true to opt in to the fused transform pass.

fn needs_all_files(&self) -> bool

Returns true if this plugin must always observe the full cache.html_files() list — even during --incremental rebuilds that only invalidated a handful of pages.

fn on_serve(&self, _ctx: &PluginContext) -> Result<(), SsgError>

Called before the development server starts serving files.