Image tools / Compress Image Online

Compress Image Online

Compress PNG, JPG, and WebP images in your browser with an adjustable quality slider. Your files are processed locally on your device and are never uploaded.

Drop image files here

or choose files

How to compress images

  1. Choose one or more image files or drag them into the box above.
  2. Pick an output format and quality, then press Compress.
  3. Download files individually or download the whole batch as a ZIP.

Shrink images before emailing, uploading, or publishing them. Pick an output format and quality level, and see the size savings before you download — everything runs locally in your browser.

Supported formats

Input: PNG, JPG, and WebP images. Output: JPG or WebP at your chosen quality level. WebP output requires Chrome, Edge, or Firefox.

Is this private?

Yes. FormatOtter runs entirely in your browser using the built-in canvas API. Your image is never sent to a server or seen by anyone. To preserve an unfinished queue across refreshes, your browser may keep a local copy on this device until processing succeeds or you clear the queue. You can even load this page and then disconnect from the internet; the tool keeps working.

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Frequently asked questions

How does browser-based compression work?

Your image is decoded and re-encoded as JPG or WebP at the quality you choose, using your browser's built-in encoder. Lower quality means a smaller file with more visible compression.

What quality setting should I use?

70–85% is the sweet spot for most photos: substantial size savings with little visible difference. Go lower for thumbnails, higher for images people will zoom into.

Why did my PNG convert to JPG?

PNG is lossless and doesn't have a quality dial, so meaningful compression requires re-encoding to a lossy format. Choose WebP as the output if you need to keep transparency.