Compress Images
Compress JPEG, PNG, and WebP images online for free. Cut file size by up to 90% with quality or target-size mode, fully private, right in your browser.
About This Tool
Reduce the file size of your images without visible quality loss. Our compressor works entirely in your browser, your photos never leave your device. Choose a quality level for quick compression, or set a target file size and let our algorithm find the optimal quality through intelligent binary search. Perfect for email attachments, website optimization, and social media uploads. Supports JPEG, PNG, and WebP formats with batch processing for up to 50 files at once.
How To Use
- Drag and drop your images into the upload area, or click to browse your files.
- Choose between Quality mode (set a percentage) or Target Size mode (set a KB limit).
- Click "Compress" and watch as each image is processed in your browser.
- Download individual files or grab all results as a single ZIP archive.
How It Works
Image compression works by reducing the amount of data needed to represent your image. When you select Quality mode, the compressor re-encodes your image using the browser's built-in JPEG or WebP encoder at your chosen quality level. Lower quality means more aggressive compression, which reduces color precision in areas where your eye is least likely to notice.
The Target Size mode uses a sophisticated binary search algorithm. It tries multiple quality levels, checking the resulting file size each time, and narrows down to the highest quality that still fits within your target. This typically converges in 7 iterations, taking less than a second even on large images.
All processing happens using the Canvas API and OffscreenCanvas inside a Web Worker. This means the compression runs on a background thread, your browser stays responsive even when processing large batches. No data ever leaves your device; there is no server involved. The original image is decoded into pixels on a canvas, then re-encoded at the target quality. For PNG files, conversion to JPEG during compression gives the biggest size reduction since PNG is a lossless format.
Frequently Asked Questions
Does compression reduce image quality?
Lossy compression does reduce quality slightly, but at 70-85% quality the difference is virtually invisible to the human eye. You can always preview the result before downloading to make sure you're satisfied with the output.
What image formats are supported?
We support JPEG, PNG, WebP, and AVIF input files. The compressed output is saved as JPEG or WebP, whichever produces the smaller file at your chosen quality level while maintaining transparency support for PNG inputs.
Is there a file size limit?
Each individual file can be up to 50MB, and you can process up to 50 files at once. For very large batches, files are processed sequentially to prevent memory issues on mobile devices.
Are my images uploaded to a server?
No, never. All compression happens 100% in your browser using the Canvas API. Your images never leave your device. You can verify this by disconnecting from the internet, the tool still works perfectly.
How does Target Size mode work?
Target Size mode uses a binary search algorithm to find the optimal quality level. It tries different quality settings and checks the file size after each attempt, converging on the highest quality that meets your size target within 7 quick iterations.
Can I compress PNG files?
Yes. PNG files are lossless, so our tool converts them to JPEG during compression, which typically reduces file size by 60-90%. If you need to keep the PNG format with transparency, use our Convert Image tool instead.