Image Compression Comparison Tool
Upload a photo and see the original next to a live-recompressed preview at any JPEG quality level, with exact file sizes and the percentage saved — all calculated locally in your browser.
How to Use the Image Compression Comparison Tool
- Click "Select an Image" and choose a photo to test.
- Drag the quality slider to any level and watch the compressed preview and file size update instantly.
- Compare the "Original Size" and "Compressed Size" stats, along with the percentage saved.
- Click "Download Compressed Version" once you're happy with the quality/size trade-off.
Why Use This Tool?
Is my photo uploaded to a server?
No. Both the original and the recompressed preview are generated and displayed entirely inside your browser using the HTML5 Canvas API. Your image is never uploaded, transmitted, or stored — every recalculation as you move the slider happens instantly on your own device, which also means there's no waiting for round-trips to a server.
Why does the file size change without changing the image dimensions?
JPEG compression uses a "quality" setting that controls how much fine visual detail is discarded during encoding — lower quality settings throw away more information and produce smaller files, while higher settings preserve more detail at the cost of file size. This tool lets you directly see and compare that trade-off in real time rather than guessing.
Why is my "compressed" file sometimes larger than the original?
If your original file was already a highly optimized JPEG, PNG, or WebP, re-encoding it as a JPEG at a high quality setting can occasionally produce a similar or slightly larger file, since re-compression isn't always more efficient than the original encoder. If this happens, simply lower the quality slider until you see a genuine size reduction.
Who should use this tool?
Web developers and site owners deciding on an image quality setting for faster page loads, photographers evaluating how much compression a shot can tolerate before quality visibly degrades, and anyone curious about the actual byte-for-byte trade-off between file size and visual fidelity will find this side-by-side comparison useful.