Add/Preserve/Modify EXIF Metadata For Images

[solonovamax]

🙋 Feature Request

The ability to add/preserve/modify EXIF metadata & ICC profile for images could be a useful feature.

😯 Current Behavior

Currently, there is some support for retaining EXIF metadata, however it is not configurable, and from what I can tell it does not preserve it when building for production:

parcel/packages/core/integration-tests/test/image.js

Lines 196 to 230 in a53f8f3

	it('should retain EXIF data', async () => {
	const b = await bundle(
	path.join(__dirname, '/integration/image-exif/resized.html'),
	);
	const imagePath = b.getBundles().find(b => b.type === 'jpeg').filePath;
	const buffer = await outputFS.readFile(imagePath);
	const image = await sharp(buffer).metadata();
	const exif = exifReader(image.exif);
	assert.strictEqual(
	exif.Photo.UserComment.toString(),
	'ASCII\u0000\u0000\u0000This is a comment',
	);
	});
	it('should remove EXIF data when optimizing', async () => {
	const b = await bundle(
	path.join(__dirname, '/integration/image-exif/resized.html'),
	{
	defaultTargetOptions: {
	shouldOptimize: true,
	},
	},
	);
	const imagePath = b.getBundles().find(b => b.type === 'jpeg').filePath;
	const buffer = await outputFS.readFile(imagePath);
	const image = await sharp(buffer).metadata();
	assert.strictEqual(image.exif, undefined);
	});

However, I'm unsure about this.

There is no support for retaining the ICC profile. Currently, it will convert images to a "web-friendly sRGB ICC profile":

withMetadata

withMetadata([options]) ⇒ Sharp

Keep most metadata (EXIF, XMP, IPTC) from the input image in the output image.

This will also convert to and add a web-friendly sRGB ICC profile if appropriate.

💁 Possible Solution

It would be nice if there was a way to do this using image transformations.

For example:

<img src="image.jpg?metadata=true"> <!-- preserve all metadata -->
<img src="image.jpg?metadata=false"> <!-- strip all metadata -->
<img src="image.jpg"> <!-- strip metadata by default, unless configured otherwise. where could this config be located? -->

<img src="image.jpg?exif=true"> <!-- preserve exif -->
<img src="image.jpg?metadata=false&exif=true"> <!-- strip all metadata except exif -->
<img src="image.jpg?metadata=true&exif=false"> <!-- preserve all metadata except exif -->

<img src="image.jpg?icc=preserve"> <!-- preserves ICC profile -->
<img src="image.jpg?icc=srgb"> <!-- convert to named ICC profile -->
<img src="image.jpg"> <!-- convert to a "web-friendly sRGB ICC profile" (current behaviour) -->

---

TODO: How should adding new metadata be handled? A possible solution could be something like

<!--
This preserves the existing EXIF (exif=true) and adds/overwrites the following EXIF tags:
- the "Copyright" tag with the value "(c) Me and Myself"
- the "Photographer" tag with the value "Me"

To not preserve the existing EXIF and only add the new tags, remove `exif=true`.
-->
<img src="image.jpg?exif=true&exif={Image.Copyright=(c) Me and Myself,Photo.Photographer=Me}">

For a list of EXIF tag names, see:

• https://exiftool.org/TagNames/EXIF.html
• https://exiv2.org/tags.html

This part needs to be investigated further.

🔦 Context

See:

• https://sharp.pixelplumbing.com/api-output#keepexif
• https://sharp.pixelplumbing.com/api-output#withexif
• https://sharp.pixelplumbing.com/api-output#withexifmerge
• https://sharp.pixelplumbing.com/api-output#keepiccprofile
• https://sharp.pixelplumbing.com/api-output#withiccprofile
• https://sharp.pixelplumbing.com/api-output#keepmetadata
• https://sharp.pixelplumbing.com/api-output#withmetadata