The Karui app compressing a 9.5 MB photo down to 230 KB, 90 percent smaller

Compression engine

A next-gen engine. Up to 90% smaller.

Karui's own next-generation encoder slashes file size dramatically while the image looks exactly the same. A 9.5 MB photo becomes 230 KB. No more watching compression wreck your shots.

Up to 90% smaller Quality preserved Next-gen engine

Format conversion

HEIC and AVIF to JPEG, just by dragging.

iPhone HEIC/HEIF photos and next-gen AVIF files convert to universally compatible JPEG in one batch. No more "this file won't open." Drop hundreds at once and let Karui handle the rest.

HEIC to JPEG HEIF AVIF WebP

The Karui app compressing a 24 MB PDF down to 3 MB

PDF compression

PDFs too, dramatically lighter.

Shrink heavy PDFs while keeping them sharp and readable. Karui re-compresses the images and fonts inside, and can downscale them further for web and mobile. Meeting decks, presentations, scanned documents all get dramatically lighter, while staying perfectly readable.

Documents Presentations Scans

The Karui app batch-compressing 128 images at once, each with its size reduction

Batch processing

Hundreds at once, in one drop.

Drop an entire folder. The SIMD-optimized engine chews through them all in seconds. 100 product shots before a deadline, or hundreds of travel photos, all optimized in a single pass with barely any wait.

Folder support Fast Bulk optimize

The Karui app cropping and resizing a photo to a 1600 px long edge

Resize & crop

Resize and crop, all in one.

Set the longest edge and resize in batch, with presets for web, social, and print. Crop to the pixel, free-form or fixed ratio. Crop, resize, and compress all finish in a single workflow.

Presets Fixed ratio Free-form

The Karui app running fully offline, nothing leaves your device

Privacy

Nothing leaves your device. 100% offline.

Your photos are never sent to the internet. Everything runs entirely on your own computer. Confidential client images and NDA work stay safe. No uploads, no leaks, no second thoughts.

Fully offline NDA-friendly No tracking

The Karui app running on both macOS and Windows

Cross-platform

The same on Mac and Windows.

The same fast, beautiful experience on either OS, with settings and presets carrying over untouched. A serious image compressor that actually runs on Windows. Finally, it's here.

macOS Windows One-time purchase

Everything Karui can do