Image Compressor
Compress images locally in your browser to reduce file size for websites, uploads and everyday sharing.
Image Compressor online
Shrink a photo's file size right in your browser: choose a quality level, optionally cap the width, and download a smaller JPEG — useful before uploading to a website, an email or a form with a size limit.
How it works
The tool decodes your image, draws it onto a canvas — scaled down first if you set a maximum width — and re-encodes it as a JPEG at the quality you choose (0.1–1.0, default 0.8). JPEG achieves its small sizes by discarding fine detail the eye barely notices; lowering the quality shrinks the file quickly at first, then visible artefacts appear below roughly 0.5. Because the output is always JPEG, any transparency in a PNG is flattened (transparent areas come out black), and the re-encode drops embedded metadata such as EXIF camera settings and GPS location.
Worked example
A 4000 × 3000 phone photo holds 12 million pixels — 36 MB as an uncompressed bitmap. Capping the width at 1920 px scales it to 1920 × 1440, about 23% of the pixels, and re-encoding at quality 0.8 typically produces a file between a few hundred KB and about 2 MB depending on scene detail. The result line on this page reports your exact before and after sizes and the percentage saved.
How to use this tool
- Choose an image file from your device.
- Set the quality — 0.8 is a good balance; go higher for print, lower for thumbnails.
- Optionally set a maximum width in pixels to downscale a large photo.
- Run the tool: the compressed JPEG downloads automatically and the page shows the size saving.
Common uses
Preparing images for websites and blogs (smaller pages load faster and score better on performance audits), fitting email attachment limits, shrinking photos for application forms and marketplace listings that cap upload size, and trimming large photo batches before archiving them.
Privacy and browser processing
All processing happens in your browser — your images are decoded and re-encoded locally and are never uploaded.
Frequently asked questions
Why did my compressed file come out larger?
If the source was already an efficiently compressed JPEG, or a very small image, re-encoding can add bytes instead of removing them — there is nothing left to squeeze. Simple graphics with flat colours also compress better as PNG than as JPEG. When the result is larger, keep your original.
What quality setting should I use?
0.8 suits most photos: visually near-identical on screens at a fraction of the size. Use 0.9 or above when the image will be printed or cropped heavily later, and 0.6–0.7 for thumbnails and previews where small size matters more than fine detail.
What happens to transparent PNGs?
The output is always JPEG, which has no alpha channel — transparent pixels are flattened to black. For logos and graphics that must keep transparency, keep the PNG or convert to WebP instead of compressing here.
Is my photo uploaded for compression?
No. Decoding, scaling and re-encoding all happen in your browser; the file never leaves your device. As a side effect, the re-encode also discards EXIF data such as the GPS location a phone camera stored in the photo.