Private optimize tool
Private Image Compressor
Reduce image size without uploading private artwork. Processing stays in your browser.
More file tasks
Compare JPG, PNG and WebP for listing photos, transparent artwork, downloadable printables and web previews.
How it works
A useful result,
without the upload.
Compress JPEG and WebP images locally with adjustable quality, a size comparison after compression and local download. The file is decoded and processed inside this browser tab, so File Preflight never receives its contents.
Worked example
A high-quality camera JPEG can often be made substantially smaller at 80–85% quality for online use.
How to use the Private Image Compressor
- Choose an image file to load it into the compressor.
- Adjust the quality slider (30-95%) to balance file size and visual quality.
- Set a maximum width to limit output dimensions if needed.
- Select your output format (WebP or JPEG).
- Click the compress button to process the image.
- Review the size reduction percentage in the status message.
- Download the compressed file for your intended use.
What happens under the hood
Images are decoded locally using the browser's Image API, then resized and re-encoded with your selected quality settings via the Canvas API. The compressor scales images proportionally to your maximum width setting and applies compression, with the final file downloaded directly to your device. All processing happens in your browser without uploading files.
Before you send the file
- Results depend on image detail, noise and the original encoding.
- Use PNG for graphics that require transparency or crisp flat-color edges.
- Keep an untouched original before compressing production artwork.
Frequently asked questions
How much can I compress without losing quality?
Most photos compress well at 80-85% quality with minimal visible difference. Higher compression (70-75%) may show artifacts in detailed areas but works for web previews.
Why use WebP instead of JPEG?
WebP typically creates 25-35% smaller files than JPEG at similar quality levels, making it ideal for web use where bandwidth matters.
When should I keep the original file?
Always keep an untouched original before compressing for production or print work. Compression is irreversible and may reduce quality needed for high-quality output.
Does compression affect all image types equally?
No - photos with lots of detail compress differently than graphics with solid colors. Test with your specific image type.
Keep an untouched original and inspect the downloaded file before replacing any production asset. Closing this tab removes the selected files from the tool.