toJpeg

Convert an image to JPEG format.

Signature

function toJpeg(input: Buffer, options?: JpegOptions): Promise<Buffer>
function toJpegSync(input: Buffer, options?: JpegOptions): Buffer

Parameters

Parameter	Type	Description
input	Buffer	Image buffer
options	JpegOptions	JPEG encoding options (optional)

JpegOptions

interface JpegOptions {
  quality?: number;  // 1-100, default: 80
}

Returns

Buffer - JPEG encoded image

Examples

Basic Conversion

import { toJpeg } from 'bun-image-turbo';

const jpeg = await toJpeg(buffer);
await Bun.write('output.jpg', jpeg);

With Quality Setting

// High quality
const hq = await toJpeg(buffer, { quality: 95 });

// Medium quality (default)
const mq = await toJpeg(buffer, { quality: 80 });

// Low quality (smaller file)
const lq = await toJpeg(buffer, { quality: 60 });

Sync Version

import { toJpegSync } from 'bun-image-turbo';

const jpeg = toJpegSync(buffer, { quality: 85 });

From HEIC

// Convert iPhone photo to JPEG
const heic = Buffer.from(await Bun.file('IMG_1234.HEIC').arrayBuffer());
const jpeg = await toJpeg(heic, { quality: 90 });
await Bun.write('photo.jpg', jpeg);

From PNG with Transparency

// Note: Transparency will be lost (converted to white)
const png = Buffer.from(await Bun.file('logo.png').arrayBuffer());
const jpeg = await toJpeg(png, { quality: 90 });

Quality Guidelines

Quality	File Size	Use Case
95-100	Large	Archival, print
85-90	Medium	Web, high quality
75-80	Balanced	General web use
60-70	Small	Thumbnails
< 60	Very small	Maximum compression

Performance

JPEG encoding uses TurboJPEG with SIMD acceleration:

• 2-6x faster than standard libjpeg
• Automatic CPU feature detection (SSE2, AVX2, NEON)

Notes

• Transparency is not supported (converted to white background)
• Quality 100 is not truly lossless (use PNG for lossless)
• Output is always RGB (not CMYK)
• EXIF data is not preserved

See Also

• toPng() - For lossless conversion
• toWebp() - For smaller file sizes
• transform() - For resize + convert in one operation