The Complete Guide to Batch Image Compression
If you have a folder of product photos, holiday pictures or blog images to shrink, doing them one at a time is slow and gives inconsistent results. Batch compression applies the same settings to every image in one go. Here's how to choose those settings and what to check before you use the results.
Understanding the quality setting
For lossy formats such as JPEG and WebP, compression is controlled by a quality value. Higher values keep more detail and make bigger files; lower values make smaller files and eventually show visible artifacts: blocky patches in smooth areas and smudged edges around text.
The relationship isn't a straight line. The first steps down from maximum quality often save a lot of space with little visible change, while pushing an already low value even lower saves less and damages the picture more. There's no single correct number, because it depends on the image. ForgePX's image compressor starts at 80, which is a sensible place to begin. Compress a few typical images, compare the result with the original at full size, and adjust from there.
Choosing the output format
- JPEG: for photographs. It doesn't support transparency, so transparent areas will be filled in.
- WebP: for photos and graphics on modern websites. Google reports lossy WebP files are 25–34% smaller than comparable JPEGs at equivalent quality. It also supports transparency.
- PNG: for screenshots, logos and images with text, where you want every pixel kept. Expect PNG files of photographs to stay large.
Metadata
Photos from cameras and phones usually carry metadata: the camera model, the date, and sometimes the GPS location where the picture was taken. If you're publishing images online, removing that information is a good idea for privacy. The compressor re-encodes each image in your browser, and re-encoding does not carry over the original metadata (EXIF, location tags). There is no option to keep it, so if you need the metadata, keep a copy of the original file.
Max compression mode
The compressor also has a Max compression mode for when file size matters more than appearance, for example to get under an upload limit. It sets the lowest quality for JPEG and WebP output; PNG has no quality setting, so the option is unavailable when PNG is selected. Expect visible quality loss, and look at the result before you send it.
A simple batch workflow
- Put the images you want to compress in one place and keep a copy of the originals.
- Drop them onto the compressor together, or select several files at once.
- Pick the output format and a quality value, then compress.
- Check the before and after sizes the tool shows, and open a couple of results at full size.
- Download the files one by one, or all together as a ZIP.
Using the same settings for the whole batch keeps the quality consistent across a page or product catalogue.
Working out the savings
The tool shows the total size before and after, so you can see exactly what you saved. As an example of the arithmetic: ten images that start at 2 MB each make 20 MB; if they come out at 400 KB each, the batch is 4 MB, an 80% reduction. Your own results depend on the images and settings, so treat this as a way of reading the numbers, not a promise.
Everything runs locally in your browser, so your images aren't uploaded to a server. Very large batches can be slow on older phones and computers.
Sources
Checked on 23 October 2026.