How to batch-compress hundreds of images at once

Compressing one image is a solved problem. Compressing four hundred of them is where most workflows fall apart. If you have ever exported a shoot, a set of product photos, or a folder of screenshots and then faced the prospect of shrinking each one by hand, you already know the problem. Here is how to do the whole folder at once.

Why one-at-a-time does not scale

Doing images individually is not just slow, it is error-prone. You lose track of which ones you have done, you apply slightly different settings each time, and a single distraction means a missed file. The manual approach also tends to push people toward whatever web tool is open in a tab — which usually means uploading each image, one by one, and waiting.

What batch compression should do

A proper batch workflow has a few requirements. It should take a whole folder at once, not make you add files individually. It should apply one consistent setting — a target format and quality — across every image. It should show progress so you know where it is. And it should hand you the results in a form you can actually use, whether that is files written back to a folder or a single archive to unzip.

Doing it locally

The batch case is exactly where uploading hurts most. Two hundred uploads, throttled by your connection's upload speed, turn a quick job into a long one. Running the compression on your own machine removes that bottleneck entirely — the files are already there, so there is nothing to transfer. It also means a folder of confidential images stays confidential, because nothing is sent anywhere.

Modern browsers can do this natively. With WebAssembly, the WebP, JPEG, and AVIF encoders run directly in the page, and the File System Access API (in Chrome and Edge) lets a web app read a folder you choose and write the compressed results straight back. On Firefox and Safari, where that API is not available, the results come back as a ZIP archive instead.

A simple workflow with Velacompress

Velacompress is built for exactly this. The steps are short:

First, open the app and drag your folder onto the drop zone — or paste images straight from your clipboard. Second, pick the output format: WebP for the best size on the web, JPEG for universal compatibility, or AVIF for the smallest files. Third, start the batch and let it run; every image is processed locally, with a live count of what is done. When it finishes, you get your compressed images back, either written to a folder or as a ZIP.

There is no upload step, no per-file limit on desktop, and no subscription — a folder of hundreds of images is one pass, not hundreds of round trips.

Try it on your next export

The next time you finish a shoot or an export, point Velacompress at the folder and compress the whole thing at once. Open the app to give it a run.