Indexable means a real URL
An <img src="https://example.com/kettle.webp" alt="…"> on a reachable page can appear in Google Images. A canvas-only lightbox with blob URLs cannot.
Why it matters
- Recipes, products and tutorials still win Image search.
- Lazy-loaded images are fine if they use real src/srcset.
- Converted files should stay on stable URLs when possible.
How to do it
- Convert and keep images in the normal uploads path.
- Do not noindex media files accidentally.
- Add images to a sitemap if you already maintain one.