Compress images without uploading them
Shrink photos and screenshots for email, websites and forms. Pick a quality level, or keep them lossless — all on your device, in bulk.
Runs on your device · 0 bytes uploaded
Drag files to reorder, or use the arrows.
How to compress Image
- Add one or more images.
- Choose the output format and quality.
- Click “Compress images” and download the result.
Private by design — and you can check
Your files are never uploaded, because there is nowhere to upload them to.
- No upload step existsFiles are read and written inside this browser tab. There is no server that could receive them.
- The browser enforces itThis page’s Content Security Policy only allows connections back to this site, which serves nothing but the app itself.
- See for yourselfOpen developer tools, watch the Network tab and run a job: no request carries your document.
- Open sourceEvery line is on GitHub, built on qpdf, pdf.js and pdf-lib.
Frequently asked questions
Are my files uploaded anywhere?
No. ZapDoc does the work inside your browser tab, using open-source engines compiled to WebAssembly and JavaScript. Your file is read from your device, processed locally, and the result is saved straight back to your device. You can check this yourself: open your browser’s developer tools, go to the Network tab, and run a job — no request carries your file.
Can I compress without losing quality?
Yes. Choose PNG for pixel-perfect lossless output. For photos, JPG or WebP at 80% quality usually looks identical and is far smaller.
Is location data removed?
Yes. Re-encoding drops hidden EXIF metadata such as GPS location and camera details.
Is ZapDoc free?
Yes. There is no sign-up, no watermark and no daily limit. ZapDoc is open source under the MIT license.
More private tools
- Resize ImageMake images larger or smaller, by pixels or percent.
- Convert ImageConvert between JPG, PNG and WebP.
- Image to Text (OCR)Select and copy text from any photo or screenshot.
- PNG to JPGConvert PNG images to JPG in bulk.
- JPG to PNGConvert JPG images to PNG in bulk.
- WebP to JPGConvert WebP images to JPG in bulk.
- JPG to WebPConvert JPG images to WebP in bulk.
- Merge PDFCombine several PDFs into one, in the order you choose.