EXIF Metadata

Write and strip EXIF metadata from JPEG and WebP images.

Perfect for AI-Generated Images

The EXIF functions are ideal for embedding metadata in AI-generated images, including prompts, model information, and generation parameters.

writeExif()

Write EXIF metadata to a JPEG or WebP image.

Signature

function writeExif(input: Buffer, options: ExifOptions): Promise<Buffer>
function writeExifSync(input: Buffer, options: ExifOptions): Buffer

Parameters

Parameter	Type	Description
input	Buffer	Input image buffer (JPEG or WebP)
options	ExifOptions	EXIF metadata to write

ExifOptions

interface ExifOptions {
  /** Image description / caption / AI prompt */
  imageDescription?: string;
  /** Artist / creator name */
  artist?: string;
  /** Copyright notice */
  copyright?: string;
  /** Software used to create the image */
  software?: string;
  /** Date/time in EXIF format (YYYY:MM:DD HH:MM:SS) */
  dateTime?: string;
  /** Original date/time in EXIF format */
  dateTimeOriginal?: string;
  /** User comment (can contain JSON or other data) */
  userComment?: string;
  /** Camera/device make */
  make?: string;
  /** Camera/device model */
  model?: string;
  /** Orientation (1-8) */
  orientation?: number;
}

Returns

Returns a Buffer containing the image with embedded EXIF metadata.

Example: Basic Usage

import { writeExif, toJpeg } from 'imgkit';

const imageBuffer = Buffer.from(await Bun.file('photo.jpg').arrayBuffer());

const withExif = await writeExif(imageBuffer, {
  imageDescription: 'Beautiful sunset over the ocean',
  artist: 'John Doe',
  copyright: 'Copyright 2026 John Doe',
  software: 'imgkit v1.4.6'
});

await Bun.write('photo-with-exif.jpg', withExif);

Example: AI-Generated Image Metadata

import { writeExif, toWebp } from 'imgkit';

// Convert to WebP first
const webpBuffer = await toWebp(imageBuffer, { quality: 90 });

// Add AI generation metadata
const withMetadata = await writeExif(webpBuffer, {
  imageDescription: 'A majestic mountain landscape at golden hour',
  artist: 'Stable Diffusion XL',
  software: 'ComfyUI',
  userComment: JSON.stringify({
    prompt: 'A majestic mountain landscape at golden hour, 8k, detailed',
    negative_prompt: 'blurry, dark, low quality',
    model: 'stable-diffusion-xl-base-1.0',
    sampler: 'DPM++ 2M Karras',
    steps: 30,
    cfg_scale: 7.5,
    seed: 123456789
  })
});

await Bun.write('ai-generated.webp', withMetadata);

Example: Sync Version

import { writeExifSync } from 'imgkit';

const withExif = writeExifSync(imageBuffer, {
  imageDescription: 'Product photo',
  copyright: 'Company Inc.'
});

---

stripExif()

Remove all EXIF metadata from a JPEG or WebP image.

Signature

function stripExif(input: Buffer): Promise<Buffer>
function stripExifSync(input: Buffer): Buffer

Parameters

Parameter	Type	Description
input	Buffer	Input image buffer (JPEG or WebP)

Returns

Returns a Buffer containing the image without EXIF metadata.

Example: Strip EXIF for Privacy

import { stripExif } from 'imgkit';

// Remove location and camera data before sharing
const imageBuffer = Buffer.from(await Bun.file('photo.jpg').arrayBuffer());
const stripped = await stripExif(imageBuffer);

await Bun.write('photo-clean.jpg', stripped);

Example: Sync Version

import { stripExifSync } from 'imgkit';

const stripped = stripExifSync(imageBuffer);

---

Using EXIF with transform()

You can also add EXIF metadata during image transformation:

import { transform } from 'imgkit';

const result = await transform(imageBuffer, {
  resize: { width: 1920, height: 1080 },
  output: { format: 'Jpeg', jpeg: { quality: 90 } },
  exif: {
    imageDescription: 'Resized hero image',
    software: 'My Image Pipeline',
    copyright: 'Copyright 2026'
  }
});

---

Supported Formats

Format	writeExif	stripExif
JPEG	Yes	Yes
WebP	Yes	Yes
PNG	No	No
GIF	No	No

PNG Not Supported

PNG uses tEXt chunks instead of EXIF. Use JPEG or WebP for EXIF metadata.

---

EXIF Field Mapping

ExifOptions Field	EXIF Tag	Tag ID
imageDescription	ImageDescription	0x010E
artist	Artist	0x013B
copyright	Copyright	0x8298
software	Software	0x0131
dateTime	DateTime	0x0132
dateTimeOriginal	DateTimeOriginal	0x9003
userComment	UserComment	0x9286
make	Make	0x010F
model	Model	0x0110
orientation	Orientation	0x0112

---

Use Cases

1. AI Image Generation Platforms

// Store generation parameters for reproducibility
const withParams = await writeExif(generatedImage, {
  imageDescription: prompt,
  software: 'MyAI Platform v2.0',
  userComment: JSON.stringify({
    model: 'sdxl-turbo',
    seed: seed,
    steps: steps,
    guidance: guidance
  })
});

2. Photography Workflow

// Add photographer attribution
const credited = await writeExif(photo, {
  artist: 'Jane Smith',
  copyright: 'Copyright 2026 Jane Smith. All rights reserved.',
  software: 'Lightroom Export'
});

3. Privacy Protection

// Strip metadata before sharing online
const safeToShare = await stripExif(userUpload);

4. Batch Processing

import { writeExif } from 'imgkit';

const files = ['img1.jpg', 'img2.jpg', 'img3.jpg'];

const results = await Promise.all(
  files.map(async (file) => {
    const buffer = Buffer.from(await Bun.file(file).arrayBuffer());
    return writeExif(buffer, {
      copyright: 'Copyright 2026 My Company',
      software: 'Batch Processor v1.0'
    });
  })
);