ImageCard

A single image tile for a media grid. The full image loads lazily — only once the tile nears the viewport (built on useIntersectionObserver) — showing a skeleton until it arrives and fading in on load. If src fails it tries fallback, then shows an error placeholder:

ImageCard(
  src = thumbUrl,
  alt = "Sunset over the bay",
  ratio = "16/9",                 // reserves space so the grid doesn't reflow
  fit = ImageFit.Cover,           // Cover | Contain | Fill | ScaleDown
  badge = Some(span("4K")),       // a corner tag
  overlay = Some(downloadButton), // hover content
  onClick = () => open(fullUrl),
)

ratio is a CSS aspect-ratio ("16/9", "1/1"); fit controls cropping; rounded (default true) rounds the corners; lazyLoad = false opts out of deferred loading. State is mirrored to data-state (loading/loaded/error) and data-inview. It is the canonical cell for a Masonry or grid layout.