Free · Private · Browser-Native

Resize & Remaster
Images & GIFs Without
Leaving Your Browser

Lanczos, Bicubic, Mitchell — professional resampling algorithms running in your browser via WebGL. Adjust color, sharpen, export. No upload, no server, completely private.

Lanczos-3 · Bicubic · Mitchell WebGL Accelerated Fully Private Always Free
Drop images or JPEG · PNG · WebP · AVIF · BMP · TIFF

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Process

How Compressy works

Images are processed using the Canvas API with hardware acceleration built into your browser. Video encoding leverages FFmpeg WebAssembly — the industry-standard encoding engine — compiled to run directly inside your browser tab. No server touches your files at any point.

01

Pick your files

Drop images or videos onto the tool, or click Browse. Batch-select as many files as you need — there is no limit imposed by Compressy.

02

Choose options

Select output format, quality level, and optional resize. For videos, pick resolution and whether to keep or strip audio.

03

Hit compress

Processing happens entirely on your CPU and GPU. Nothing leaves your device. Progress updates in real time, per file.

04

Download results

Download files individually or grab them all at once. A savings summary shows exactly how much space you reclaimed.

Formats

Input & output formats

Compressy accepts the most common image and video formats and converts them to modern, highly-compressed formats optimised for web delivery and storage efficiency.

WebP Image

Google's modern image format. Roughly 30% smaller than JPEG at equivalent visual quality, with full alpha transparency support.

Lossy & lossless · Universal browser support
JPEG Image

The universal standard for photographs. Compressy re-encodes at your chosen quality to strip metadata and reduce file weight.

Lossy · Maximum compatibility
PNG Image

Lossless compression with full transparency. Ideal for screenshots, logos, and graphics where pixel-perfect accuracy matters.

Lossless · Alpha transparency
WebM Video

Open-source video container with VP9 encoding. Excellent compression ratios for web streaming, with no licensing fees or royalties.

VP9 codec · Open standard
MP4 Video

The most widely supported video format. H.264 encoding ensures playback on every device — from browsers to smart TVs and mobile.

H.264 codec · Maximum device compat
Accepted inputs

Images
JPEG · PNG · GIF · BMP · TIFF · WebP · AVIF

Videos
MP4 · MOV · AVI · MKV · WebM · FLV · 3GP

Why Compressy

Privacy-first compression

Most online compressors upload your files to a remote server, process them there, and hand them back. Your photos and videos transit foreign infrastructure, sit in temporary storage, and may be subject to data retention policies you have never read.

Compressy takes the opposite approach. When you compress a file, it never leaves your device. The processing happens inside a WebAssembly sandbox running in your own browser tab. No account required. No email. No tracking cookies. No ads that know what you compressed.

Compressy is part of RuntimeHub — a suite of free, browser-native tools built on one principle: your files are yours, full stop.

FAQ

Frequently asked questions

Yes, completely free. Compressy is supported by unobtrusive display advertising. There are no premium tiers, no file size limits, no conversion caps, and no account required.
Never. All processing happens locally in your browser using the Canvas API for images and FFmpeg WebAssembly for video. Your files do not touch any server — not ours, not anyone else's.
Video encoding is computationally intensive. FFmpeg WebAssembly runs on your CPU in a single thread. A 30-second clip may take 1–3 minutes depending on your hardware. Image compression via Canvas API is near-instant by comparison.
For images, 80–85% WebP quality is generally indistinguishable from the original at roughly half the file size. For web thumbnails, 70–75% is excellent. For archival, stay at 90+. For video, "Balanced" is a solid starting point for most social and web use cases.
There is no artificial limit imposed by Compressy. The practical limit is your browser's available memory. For images, hundreds of files in a single batch work fine. For video, we recommend processing one or two large files at a time to avoid memory pressure.
All modern browsers are supported for image compression. Video compression relies on WebAssembly and works best in up-to-date versions of Chrome and Edge. Firefox and Safari support improves with each browser release — keep your browser updated for the best experience.