Batch Image Compressor

📖 About this tool

Batch Image Compressor shrinks a whole folder of pictures at once, entirely inside your browser. It is built for the moments when a single-image optimiser becomes tedious: uploading product photos to a marketplace that caps every file at 2 MB, attaching a dozen screenshots to a quotation email, or shrinking a photo set before it goes into a CMS. Drop the whole selection in, wait a few seconds, and download either individual files or one ZIP archive.

Two things set it apart from a one-at-a-time optimiser. First, you can cap the maximum width before encoding, so a 4000-pixel camera original does not waste space on a page that only ever renders 1600. Second, the result table lists the before and after byte size of every single file together with the percentage saved, which makes it obvious when one stubborn image refuses to shrink.

✨ Features

• Two compression modes - a quality slider from 10% to 95%, or a target size in kilobytes that the tool hits by binary-searching the closest acceptable quality value.
• True batch processing - select or drag in any number of files, with a progress bar advancing per image.
• Output format control - keep the original format or force JPG, WebP or PNG across the whole batch.
• Automatic PNG to WebP - PNG is lossless, so a quality slider does nothing to it; enabling this switch changes the codec instead and usually cuts the file size by an order of magnitude.
• Maximum width limit - enter 1600 and every wider image is rescaled proportionally, height computed automatically so nothing is distorted.
• Per-file comparison - each row shows before to after size and the saving percentage.
• One-click archiving - download every result as a ZIP, original file names preserved.
• Runs locally - nothing is uploaded, and it keeps working offline.

🚀 How to use

1. Click Choose images or drag files onto the dashed area; multiple selection is supported. Load samples if you just want to see how it behaves.
2. Pick a mode: move the slider for quality, or type a target size in KB such as 200.
3. Optionally set the output format, the maximum width, and whether PNG should become WebP.
4. Press Compress. When the progress bar completes, the result list shows the size change per image.
5. Use the per-row Download button, or Download all as ZIP.

⚠️ Notes

• Compression is lossy. Lower quality means more lost detail, so calibrate on the samples first.
• Already small files have little left to squeeze; a saving near zero percent is normal.
• Re-encoding strips EXIF and other metadata. Do not use this tool on files whose capture data you need.
• Forcing PNG can make files larger, because PNG is lossless.
• Very large images (tens of thousands of pixels per side) hit browser canvas limits - cap the width first.