How to use the image compressor
- Drop images onto the upload area, paste them from your clipboard, or click Choose files. Up to 50 files can be added at once.
- Choose a mode. Quality sets the encoder quality directly (80% is a good default). Target size makes the compressor lower quality, then dimensions, until each image fits under a size such as 200 KB.
- Optionally change the output format. Converting PNG photos or screenshots to WebP or JPG often halves the file size.
- Review the before and after preview and the space saved for each image.
- Download images one at a time or grab them all as a zip.
Features
- JPG, PNG and WebP input and output, with batch processing
- Quality slider or target file size in KB
- Smart PNG compression using palette quantization, or lossless PNG
- Before and after preview on a checkerboard so transparency is visible
- Keeps the original when compression wouldn't make the file smaller
- Everything runs on your device using the Canvas API; nothing is uploaded
What does an image compressor do?
An image compressor re-encodes a picture so it takes up less storage and loads faster, ideally without a visible difference. For JPG and WebP that means lossy encoding: the encoder discards fine detail that eyes rarely notice, and the quality setting controls how aggressive it is. For PNG, which is lossless by design, the main way to get a much smaller file is to reduce the number of colours to a palette of at most 256, which is what the smart PNG option does.
This tool does all of that inside your browser. Your device decodes the image, redraws it onto a canvas and encodes it again with the settings you choose. There is no upload, no queue and no server keeping a copy.
How much smaller will my images get?
It depends on the source. A photo straight from a phone camera at quality 80 typically shrinks by 50–80% because cameras save at very high quality. A JPG that has already been compressed once will shrink much less, and pushing it further mostly adds artefacts. PNG screenshots with flat colours often drop 60–80% with smart PNG compression, while PNG photographs benefit most from converting to WebP or JPG instead.
The target size mode is useful for upload limits: set 200 KB for a form that only accepts small files, and the tool searches for the highest quality that fits, shrinking the dimensions only if it has to. If a target is unreachable without ruining the image, the result says so rather than silently degrading it.
Supported formats
Input: JPG/JPEG, PNG and WebP. Output: the same three formats. WebP output requires a browser that can encode WebP, which includes current Chrome, Edge and Firefox; the option is disabled automatically where it isn't available. HEIC photos from iPhones aren't supported yet because browsers can't decode them natively; a HEIC to JPG converter is on the roadmap.
Tips for the smallest files
A few habits make a bigger difference than any single setting:
- Resize first. A 4000-pixel-wide photo shown at 800 pixels wastes most of its bytes; use the Image Resizer, then compress.
- Prefer WebP for the web: it's usually 25–35% smaller than JPG at the same visual quality and supports transparency.
- Stay around quality 70–85 for photos. Below 60 the savings shrink while artefacts become visible.
- Use lossless PNG only for graphics that must be pixel-exact, such as logos with sharp edges.