About the Bulk Image Compressor
This compresses a whole set of images at once and returns them as a single ZIP — the batch version of the image compressor. It's for when you have a folder of photos to slim down together: shrinking a gallery before publishing, cutting a set of images to fit an upload limit, reducing email attachment sizes, or reclaiming storage across many files without repeating the work image by image.
How it works
Add a batch of images, set a single quality level and output format (JPG, WebP or PNG), and the tool re-encodes each image on a canvas in your browser at that setting, then bundles them into a ZIP. It reports the total size before and after, so you can see the overall saving. WebP typically gives the smallest files at a given quality; JPG is broadly compatible.
Assumptions and behaviour
- One quality and format applies to the whole batch.
- The tool shows the combined original vs compressed size, so you can judge the saving across all files.
- Image dimensions are unchanged — this reduces size by compression, not by resizing (pair with the Bulk Resizer to do both).
- Outputs are delivered in a single ZIP.
Limitations
- PNG is lossless, so the quality setting barely shrinks PNGs — convert the batch to JPG or WebP for real savings on photographic PNGs.
- Everything runs in your browser's memory, so very large batches of high-resolution images can be slow or hit limits on modest devices; use smaller batches if needed.
- Lossy compression degrades quality at low settings, and re-compressing already-compressed images loses a little more each time.
- The same quality is applied to every image, regardless of how each one responds.
Privacy
All compression runs entirely in your browser with the Canvas API. None of your images are uploaded — they're processed on your device and zipped locally.
Get FreeMyTask as an app