Image Compressor
Fast, multi-threaded image compression — shrink many images at once by quality or to a target file size, with WebP/JPEG output and optional resizing, entirely in your browser.
Prefer the terminal? See the CLI equivalent →About the Image Compressor
- Batch — many images at once
- Multi-threaded processing
- Compress to a target file size
- Download all as a ZIP
- Instant results
- 100% private — runs in your browser
- Free, no sign-up
This tool shrinks image file sizes so pages load faster and attachments fit under upload limits — a whole batch at once. Drop in JPEGs, PNGs, WebP, or GIFs, choose how hard to compress, and download the smaller files individually or as a single ZIP.
Everything runs in your browser using the Canvas API: each image is decoded, optionally downscaled, and re-encoded to WebP or JPEG locally. Nothing is uploaded, so private screenshots and photos stay on your device, and re-encoding strips EXIF and GPS metadata as a side effect. There are no file-count or size limits beyond your own machine.
Two ways to compress: pick a quality level and see how small each file gets, or set a target file size (in KB) and let the tool search for the highest quality that fits your budget. When a "compressed" result would actually be larger than the original — common for already-optimised files or flat PNG graphics — the original is kept instead, so you never end up with a bigger file.
How to use it
- Drop images onto the box, or click to choose several at once.
- Pick an output format (WebP is usually smallest), then compress by quality or to a target size in KB.
- Optionally cap the largest dimension to downscale big photos before compressing.
- Review the per-file and overall savings, then download files individually or all together as a ZIP.
Getting the smallest files
- WebP
- Usually 25–35% smaller than JPEG at the same quality, with transparency support. The best default for the web.
- Quality ~75%
- A good balance for photographs — visually near-identical to the original at a fraction of the size.
- Target size
- Binary-searches the quality to fit a KB budget. Useful for upload limits or email attachments.
- Max dimension
- Downscaling a 4000px phone photo to 1600px often shrinks the file far more than quality alone.
Frequently asked questions
Are my images uploaded anywhere?+
No. Decoding, resizing, and re-encoding all happen locally in your browser with the Canvas API. Your images never leave your device — there is no server — so it is safe to compress private photos and screenshots.
How is this different from the Image Converter?+
The Image Converter focuses on converting a single image between formats with a live before/after preview. The Image Compressor is built for shrinking many images at once, with a target-file-size mode, overall savings, and a one-click ZIP of the whole batch.
Why was one of my files "kept original"?+
Re-encoding does not always help — already-optimised JPEGs and flat PNG graphics can come out larger. When that happens the tool keeps the original bytes, so a file is never made bigger by compressing it.
Can it compress PNGs a lot?+
The browser’s Canvas API is not a dedicated PNG optimiser, so lossless PNG re-encoding rarely shrinks much. For big savings on PNG photos or screenshots, choose WebP as the output format — it typically produces far smaller files.
What happens to animated GIFs?+
They are compressed to a single still frame. The Canvas API cannot re-encode animation, so use this tool for static images; keep the original if you need the animation.
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