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Image Compressor - Reduce Image File Size Online

About the Image Compressor

Large image files slow down page loads, eat into storage quotas, and frustrate users on slower connections. This compressor uses the browser's built-in Canvas API to re-encode your images at a lower quality setting, producing significantly smaller files with minimal visible loss. You control the trade-off between file size and visual fidelity using a quality slider, and a side-by-side preview lets you compare the original and compressed versions before downloading.

Because the tool runs entirely in your browser, your images are never uploaded to any server. This makes it suitable for sensitive or confidential images that should not leave your device.

How to Use the Image Compressor

Drop an image onto the upload area or click to select a file. Choose your desired output format (JPEG, WebP, or PNG) and adjust the quality slider. The compressed preview and new file size appear in real time. When you are happy with the result, click the download button to save the compressed image.

Features

  • Quality slider. Fine-tune compression from 0 to 100 for JPEG and WebP output, with live file-size feedback.
  • Side-by-side preview. Compare original and compressed images visually before committing to a download.
  • Multiple output formats. Export as JPEG, WebP, or PNG regardless of the original format.
  • File-size comparison. See original and compressed sizes at a glance, along with the percentage reduction.
  • Fully private. All processing uses the Canvas API in your browser. No data leaves your device.

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Frequently Asked Questions

How does browser-based image compression work?
The tool draws your image onto an HTML Canvas element, then exports it using the Canvas API's toBlob method at the quality level you choose. For JPEG and WebP, the quality parameter controls how aggressively the encoder discards visual detail to shrink file size. For PNG, the output is lossless, so the quality slider has no effect. All processing happens in your browser using built-in APIs, with no server involved.
Which image formats are supported?
You can upload any image your browser can display, including JPEG, PNG, WebP, GIF, BMP, and AVIF (where supported). The output format can be set to JPEG, WebP, or PNG. Choosing a different output format from the original is a quick way to convert between formats while compressing at the same time.
Why does the quality slider have no effect on PNG output?
PNG is a lossless format, meaning it preserves every pixel exactly. The Canvas API ignores the quality parameter when exporting to PNG. If you need a smaller file, switch the output format to JPEG or WebP, which support lossy compression and respond to the quality slider.
Is my image uploaded to a server?
No. The entire compression process runs locally in your browser using the Canvas API. Your image is never sent over the network. You can verify this by disconnecting from the internet and using the tool offline.