Allow preserving image metadata when using Astro components

[DavidOsipov]

Summary

Add a simple config option to astro.config.mjs to let users keep image metadata (XMP, EXIF, etc.) when using the built-in <Image> and <Picture> components.

Background & Motivation

Right now, when Astro processes images, it strips all the useful metadata. This is a problem because this metadata is not just junk data; it is important for many real-world reasons:

• SEO: Search engines like Google read this data to understand and rank images. It contains keywords, descriptions, and context. When Astro removes it, it hurts our site's image SEO.
• Copyright and Licensing: Photographers, artists, and companies embed their copyright, author name, and license information directly in the files. Stripping this is bad practice and can even cause problems with image licensing.
• Accessibility and Context: Metadata can store descriptions and other context that helps tools and people understand the image.

The only way to fix this today is to build a whole custom image service just to add one function call (.keepMetadata()). This is too much work for something that should be a simple switch. We are forced to do a lot of complex setup for a very common need.

Goals

• Give users a simple, one-line config option to keep their image metadata.
• Stop forcing users to write a custom service for this basic task.
• Improve the SEO of images that Astro processes by default.
• Make sure creator and copyright information is not lost during the build.

Example

I propose adding a new boolean option to the image config in astro.config.mjs.

Let's call it preserveMetadata.

// astro.config.mjs
import { defineConfig } from 'astro/config';

export default defineConfig({
  image: {
    // Just add this one line.
    // Default would be `false` to keep the current behavior.
    preserveMetadata: true,
  },
});

When preserveMetadata is set to true, Astro would simply tell the underlying Sharp service to use its .keepMetadata() function. This would preserve all existing metadata from the source image in the final output.

The default should be false to avoid changing the current behavior for existing projects. This makes it a non-breaking, opt-in feature.