Yet Another HTML Img Inliner

Inline every <img src> (and srcset entries) in an HTML file into base-64 data: URLs – works for both local files and remote images – zero dependencies.

npx -y yet-another-html-img-inliner input.html -o output.inlined.html

What’s new in v2.0?

• Remote support – downloads http(s): and protocol-relative (//…) images and inlines them.
• Skips existing data: URLs.
• Respects the same --maxMB size guard for remote and local images.
• Caches repeated remote URLs to avoid multiple downloads.
• All the previous local-handling goodness remains.

Why another inliner?

• Local + remote support – embed assets from your filesystem and from the web.
• Handles srcset as well as src.
• Understands URL-encoded paths (e.g. %20 for spaces) & strips ?query#hash.
• Case-insensitive fallback for local files (useful on Windows / mixed-case exports).
• Size guard (--maxMB, default 10 MB per image) applies to both local and remote sources.
• Single ~500-line script, no runtime deps—perfect for one-off builds or CI.

Install / Run

| use-case | command | | ------------------------- | -------------------------------------------------------------------------------------------------- | | one-off (recommended) | npx -y yet-another-html-img-inliner input.html -o output.html | | global | npm i -g yet-another-html-img-inliner → yet-another-html-img-inliner input.html -o output.html | | project dep | npm i --save-dev yet-another-html-img-inliner → add it to your build scripts |

CLI

yet-another-html-img-inliner <input.html> [-o output.html] [--root DIR] [--maxMB 10]

Options:
  -o           Write result to file (omit to pipe to stdout)
  --root DIR   Resolve relative image paths from DIR instead of input file’s folder
  --maxMB N    Skip images larger than N megabytes (default: 10)
  -h, --help   Show this help

Examples

Inline and overwrite (guarded):

yet-another-html-img-inliner src/index.html -o dist/index.html

Pipe to stdout:

yet-another-html-img-inliner email.html > email.embedded.html

Images live in a sibling folder:

yet-another-html-img-inliner build/page.html --root build/assets -o build/page.inline.html

Remote images too:

yet-another-html-img-inliner newsletter.html -o newsletter.inline.html

Caveats

• Adds ~33 % size overhead (base64). Heavy pages can balloon quickly.

• Only PNG, JPEG, GIF, SVG, WebP, BMP, ICO & AVIF are recognised. Others fall back to application/octet-stream.

• Skips data: URLs (already inline).

• For remote images:

  • Follows up to 5 redirects.
  • Aborts downloads exceeding --maxMB limit.
  • Requires network access at runtime.

• Refuses to overwrite the input file; choose a different -o.

Do you want me to also add an **“Advanced”** section to the README describing the redirect, timeout, and caching behavior of remote inlining? That could make the new behavior crystal-clear.