Compress image files in your browser
Choose a photo, set the quality slider and compress image files to a smaller JPG without uploading anything to a server.
Last updated
Your files never leave your device. Everything is processed in your browser and nothing is uploaded.
How to compress image files
- Press Choose image, or drop a JPG, PNG or WebP file onto the box.
- Move the quality slider. 70 is a good starting point for photos.
- Compare the original size and the new size in KB, shown under the slider.
- Press Download to save the compressed JPG to your device.
- If the file is still too big, lower the quality a little and download again.
How the image compressor works
The tool draws your picture onto an HTML canvas in your browser and saves it again as a JPEG at the quality you pick. JPEG compression works by discarding fine detail the eye is least likely to notice, such as tiny colour changes in skies, skin and shadows. Lower quality throws away more detail and gives a smaller file.
Because the whole process happens on your device, your photo is never uploaded. The width and height stay the same, so the saving comes purely from how the pixels are encoded.
Formula
Sizes are shown in kilobytes: KB = bytes ÷ 1024. Saving = (original size − new size) ÷ original size × 100%.
The quality setting runs from 10 to 95 and is passed to the browser's JPEG encoder as a value from 0.10 to 0.95. Transparent areas in PNG or WebP files are filled with white, because JPEG has no transparency.
Example
A 3.2 MB phone photo (3,276.8 KB) saved at quality 70 commonly lands somewhere between 600 and 900 KB. If it comes out at 700 KB, the saving is (3,276.8 − 700) ÷ 3,276.8 × 100, or about 78.6%.
A small PNG logo with flat colours can actually get bigger as a JPEG. When that happens the tool tells you, and you should keep the original file.
Tips and common mistakes
Start at 70, then adjust
A quality between 60 and 80 usually looks the same as the original on a phone screen. Below about 40, blocky patches and halos around sharp edges start to show.
Always start from the original
Every JPEG save loses a little more detail. Compress the original photo rather than a copy you have already compressed.
Use JPG for photos, not logos
Screenshots, text and logos turn fuzzy as JPEG. Keep those as PNG and use this tool for photographs.
Shrink scans before combining them
Phone scans of documents are often several megabytes each. Compress them first, then merge the pictures into one PDF with our JPG to PDF tool to stay under email limits.
Keep alt text short and useful
If the image is going on a website, describe it in one plain sentence. The word counter helps you keep alt text and captions concise.
Frequently asked questions
Are my images uploaded to a server?
No. Images are compressed in your browser with the canvas API. Your files never leave your device, and nothing is stored.
Which formats can I compress?
You can open JPG, PNG and WebP files. The result is always saved as a JPG, which gives the biggest savings for photos.
Will the image dimensions change?
No. Width and height stay exactly the same; only the file size changes.
Is there a file size limit?
There is no upload limit because nothing is uploaded, but very large images, above roughly 50 megapixels, can be slow or fail on phones with little memory.
Is location and camera data kept?
No. Saving through the canvas strips EXIF metadata such as GPS location and camera model, which is good for privacy when you share photos.