Only JPG

Today’s Impact

How We Estimate Carbon

Smaller files mean every future download uses less energy. We estimate potential reduction using the Sustainable Web Design model: data-transfer energy × grid carbon intensity.

• Energy intensity (SWDM v3): 0.81 kWh per GB transferred.
• Global default grid intensity: 442 g CO₂e per kWh.

This reflects data-transfer only and excludes the one-time CPU cost to compress on your device.

Your Privacy & Our Stats

Your images stay on your device. All compression happens locally in your browser. We don’t upload or store files.

To show impact, we collect anonymous counts (image totals, bandwidth saved). To prevent spam, IPs are used for short-lived rate-limits and are never stored with stats.

You’re in control. Opt out right here—or use the settings panel (gear above) any time:

Estimated Downstream Savings

The stats above show direct savings from avoiding uploads and downloads. This panel estimates the additional, collective impact of sharing smaller files. We assume 10% of images are shared and each is downloaded an extra 3 times.

Thanks Everyone!

OnlyJPG is built on the shoulders of giants. We’re grateful to the open-source community and service providers who make this tool possible.

Jpegli

The core high-fidelity JPEG encoding library from Google that powers the app's compression engine.

Emscripten

The compiler toolchain used to compile Jpegli's C++ codebase into high-performance WebAssembly.

Three.js

The 3D library used to render the interactive globe in our statistics header.

Bun

The fast JavaScript runtime powering our anonymous statistics backend.

Material Web

Provides the high-quality, themeable user interface components like sliders, switches, and cards.

PDF.js

Enables client-side rasterization of PDF files into images for processing.

libheif-js

A WebAssembly library that enables the browser to decode HEIC/HEIF images.

fflate

An extremely fast, lightweight JavaScript library for creating ZIP archives for downloads.

ExifReader

A JavaScript library used to parse EXIF, ICC, and XMP metadata from source images.

Google Fonts

The service used to deliver the Atkinson Hyperlegible and Roboto typefaces.

SQLite

The embedded database used by our statistics server for fast, reliable data storage.

Nginx

The high-performance web server that serves our static application and API proxy.

Solar System Scope

Provides the high-resolution Earth textures for the globe visualization, licensed under CC BY 4.0.

Live Cloud Maps

The source for the cloud and specular map overlays, derived from EUMETSAT data and available under CC0.

Terms of Service

OnlyJPG is a free tool provided “as-is,” without warranties. Always keep backups of your originals.

Use it for good. Don’t use it for illegal, malicious, or abusive purposes.

We aren’t liable for issues, data loss, or existential crises arising from its use.