This image compressor reduces file size by re-encoding your image at a lower quality setting directly in the browser. You upload a JPG, PNG, or WebP file, adjust a quality slider between 0 and 1, and download the compressed result. The tool displays the original and compressed file sizes so you can judge the tradeoff before saving. No data leaves your device — the entire process runs client-side.
The image compressor draws your uploaded image onto an HTML Canvas element, then calls the Canvas API’s toBlob method with two arguments: the output MIME type and a quality parameter between 0 and 1. The browser’s built-in encoder handles the actual compression. At quality 1.0, the encoder preserves maximum detail. At lower values, it applies stronger quantization to the image data, discarding information the human eye is least likely to notice.
This approach keeps your images private because the file never travels to a server. It also eliminates upload and download latency — compression happens as fast as your device can re-encode the pixels.
Lossy compression permanently removes image data to achieve smaller files. JPG and WebP both use lossy compression by default. The encoder analyzes blocks of pixels, discards fine detail that falls below a threshold set by the quality parameter, and stores an approximation. Lower quality means more data discarded and a smaller file. The removed detail cannot be recovered.
Lossless compression reduces file size without discarding any image data. PNG uses lossless compression — it finds patterns and redundancies in the pixel data and encodes them more efficiently. When you compress a PNG with this tool, the quality parameter has limited effect because the PNG encoder does not perform lossy quantization. To meaningfully reduce a PNG’s file size, you need to either reduce its dimensions (with an image resizer) or convert it to a lossy format like JPG or WebP (with an image converter).
Use lossy compression for photographs and complex images where small detail loss is acceptable. Use lossless compression for screenshots, diagrams, and images with text or sharp edges where every pixel matters.
The actual savings depend on image content, dimensions, and the original file’s encoding. Images with large areas of similar color compress more than images with fine detail throughout. These figures represent typical results for photographs:
| Format | Quality Setting | Typical File Size Reduction | Visual Impact |
|---|---|---|---|
| JPG | 0.80 | 40 – 60% | Negligible — differences invisible at normal viewing |
| JPG | 0.50 | 60 – 80% | Minor artifacts in gradients and fine textures |
| JPG | 0.20 | 80 – 90% | Visible blocking artifacts, suitable for thumbnails |
| WebP | 0.80 | 50 – 70% | Negligible — WebP achieves better ratios than JPG |
| WebP | 0.50 | 70 – 85% | Minor softening in detailed areas |
| PNG | Any | 0 – 10% | None — PNG is lossless, quality slider has minimal effect |
Uncompressed pixel data grows with resolution. This table shows typical file sizes for photographs saved as JPG at quality 0.80, which offers a practical balance between size and fidelity:
| Dimensions | Use Case | Uncompressed (approx.) | JPG at Quality 0.80 |
|---|---|---|---|
| 640 x 480 | Email attachment, thumbnail | 900 KB | 40 – 80 KB |
| 1280 x 720 | Blog post, social media | 2.7 MB | 100 – 200 KB |
| 1920 x 1080 | Website hero image | 6.2 MB | 200 – 500 KB |
| 3840 x 2160 | 4K display, print | 24.9 MB | 800 KB – 2 MB |
| 4032 x 3024 | Smartphone camera photo | 36.6 MB | 1 – 3 MB |
No. This tool only adjusts encoding quality — the pixel dimensions stay the same. To change width and height, use the Image Resizer. Combining both — resizing then compressing — produces the smallest files.
PNG uses lossless compression. The browser’s PNG encoder does not use the quality parameter the same way JPG and WebP encoders do. To reduce a PNG significantly, convert it to JPG or WebP first using the Image Converter.
For most photographs, 0.70 to 0.85 gives a good balance — file size drops by half or more, and the visual difference is difficult to spot at normal viewing distances. For thumbnails or previews where size matters more than detail, 0.40 to 0.60 works well.
You can, but each round of lossy compression degrades quality further without proportional size savings. Compress once from the original file at the quality level you need.
No. The image never leaves your browser. The tool uses the Canvas API to re-encode the file locally on your device.
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