Batch Image Compressor

What a batch compressor does to each file

Every image in the batch is decoded, redrawn at its original width and height, and saved as a JPG at the quality you chose. That makes the output uniform: PNG, WebP and JPG inputs all come out as JPG, transparent areas are filled with white, and hidden metadata — camera model, capture time, GPS location — is left behind.

Using one quality level for every file is what makes batches fast and predictable. It doesn't adapt per photo, so a mixed set (a few screenshots among many photos) is best split: compress the screenshots separately at a higher quality to keep their text crisp.

Estimating the result before you start

Files straight from a phone camera are saved at high quality, so re-saving them at 70% often cuts their size by half or more. Images that were already compressed — downloads from social media, chat apps or websites — have less left to give, and some may barely change.

There's no fixed cap on how many files you can add, but each photo has to be decoded into memory while it's processed. A 12-megapixel photo takes about 48 MB of memory once decoded (four bytes per pixel), so a laptop copes with large batches easily while an older phone may struggle. If the browser tab slows down, work in groups of 20–30.

Common reasons to compress in bulk

• Emailing a set of photos: 30 photos at 3 MB each come to about 90 MB, far over Gmail's 25 MB attachment limit. Bring each one down to roughly 700 KB and the whole set, about 21 MB, fits in one email.
• Uploading a product catalogue or property listing where every image should load quickly.
• Preparing images for a website or blog, where dozens of full-size photos would make pages slow.
• Submitting coursework, reports or insurance claims through portals with a per-file size limit.