How to use the image compressor
- Choose one or more images. Compression starts right away and each row shows the original size, the new size and the percentage saved.
- Move the Quality slider. Lower numbers give smaller files and more visible loss. The results update a moment after you stop moving it.
- Optionally set a maximum width in pixels. Wider images are scaled down, and narrower ones are left alone.
- Select Compare on any row to see the before and after side by side, then Download compressed images. One image downloads directly and several arrive in a zip.
How compression works here
Each image is decoded by your browser, drawn onto a canvas at the final size and saved again as JPG, WebP or PNG with the quality you chose. Lossy formats (JPG and WebP) get smaller by discarding detail the eye notices least. Images are processed one at a time and each canvas is released before the next one, so a batch of dozens of photos does not pile up in memory. Nothing is uploaded.
What the output format options do
The default is automatic, which picks the format per file.
- Automatic keeps JPG as JPG and turns everything else, including PNG, into WebP, which keeps transparency and is usually much smaller.
- JPG works for photographs and is understood everywhere. Transparent areas become white.
- WebP is smaller than JPG at similar quality in most cases. Current browsers open it, but some older programs do not.
- PNG re-saves without loss. The quality slider does nothing, and the file may not shrink at all. The only ways to shrink a PNG here are a smaller width or a different format.
When the original is kept
Re-saving an image that is already heavily compressed can make it larger. If the new file would be at least as big as the original, with the same format and size, the tool keeps your original file and marks the row as already well compressed. It never gives you a bigger file in that situation.
What is lost along the way
Lossy compression cannot be undone, so keep your originals. Metadata such as the camera model, date and GPS location is not carried over, which helps privacy. Embedded color profiles are also dropped, so images with unusual wide-gamut profiles may shift slightly in color. Animated GIFs and WebPs are reduced to their first frame.
Limits
You can add up to 100 images, 25 MB each and 100 MB in total. Files your browser cannot decode, including HEIC photos, are reported by name with a plain message. Related tools: resize dimensions with the image resizer, change format with the image converter, or put photos in a document with image to PDF.
Assumptions and limits
- Images are processed on your device. Nothing is uploaded or stored.
- Quality numbers are the browser encoder setting from 10 to 100. They are not a standard scale, so the same number can give different sizes in different browsers.
- PNG is lossless. Only resizing or converting to another format can make a PNG much smaller.
- Metadata and color profiles are not preserved. Animated images keep their first frame only.
- Limits are 100 images, 25 MB per image and 100 MB in total. WebP output depends on browser support.
Frequently asked questions
What quality setting should I use?
For photos on the web, 70 to 80 is a common starting point. Check the before and after view. If you see blocky areas or smeared edges, raise the number.
Why can I not shrink my PNG with the slider?
PNG stores every pixel exactly, so there is no quality to trade away. Convert it to WebP or JPG, or set a maximum width, to reduce its size.
Why does a row say the original was kept?
Compressing that image again would have produced a larger file. The tool keeps the original so you never end up with a worse result.
Can I compress many photos at once?
Yes, up to 100 at a time. They are processed one after another, and the download is a single zip file.
Will my photo orientation change?
No. The rotation stored in the photo is applied when the image is drawn, so it looks the same as in your photo app, and the new file is stored upright.