Bulk Image Compressor

Add as many images as you like, by dragging them in or with the Add More button. When you press compress, the files are handled one after another, not all at once. Each one is decoded, re-encoded at your quality setting in a Web Worker, and shown next to its original with both file sizes. Working through the list in order keeps memory use predictable, which matters on phones and older laptops where decoding dozens of large photos at the same time could crash the tab.

A single failed file does not stop the batch. It is marked as an error and the rest continue.

• Quality (default 60%): the same encoder quality is used for every file.
• Output format: WebP (default), JPG, PNG or AVIF. Every image in the batch is converted to the format you pick.
• File names: each result is named compressed- followed by the original name and the new extension.
• Download: one button builds a ZIP of all finished files in the browser. You can also save individual results from their cards.
• Limits applied to every file: long side capped at 4096 px; outputs above 1 MB (2 MB above 90% quality) are reduced further in up to 10 smaller steps, which can lower both quality and dimensions.

Changing the quality or format after a run clears the results so you never download a mix of old and new settings.

AVIF can produce smaller files than WebP at similar quality, but saving AVIF depends on your browser's built-in encoder, and many browsers cannot do it. When the browser returns a different format, the tool now stops and tells you rather than handing you a PNG with an .avif name. If you see that message, choose WebP.

A batch setting is a compromise. A quality that looks fine on a busy outdoor photo can show blocky artifacts on a portrait with smooth skin, and screenshots with text tend to need higher quality than photos. Two habits help:

• Group similar images and run them as separate batches, for example product photos in one batch and diagrams in another.
• Open a few results at full size with the preview before downloading the ZIP. The size column shows the savings, but only your eyes can judge the quality.

If the goal is a size limit rather than a look, resize first with the Bulk Image Resizer. Fewer pixels reduce size more reliably than lower quality.

• Metadata, including EXIF location data and colour profiles, is removed from every file.
• PNG output reduces the number of colours (to roughly 2,450 at 60% quality), so photos saved as PNG can show banding.
• HEIC files can only be read in browsers that display HEIC, which in practice means Safari.
• Very large batches are limited by your device's memory, since all results are kept in the tab until you download them.

Every file is compressed in your browser, and the ZIP is assembled in your browser too. No image is uploaded. Closing the tab discards everything.