Useful Utilities

Image Compressor

Re-encode an uploaded image as a JPG at a chosen encoder quality and optional maximum width, reporting original and compressed file sizes and the saving percentage.

Fill in the values and calculate

Upload an image*PNG, JPG, GIF, WebP and other readable images all work as input
JPG quality (%)Lower values mean smaller files and softer detailDefault 70
Maximum widthThe height follows by the same ratio; 0 leaves the size untouchedDefault Keep original size

The form sends itself back to this page — results print below, computed on the server.

No results yet: fill the form above and press Calculate.

About Image Compressor

ImageMagick reads the upload, resizes it down if you picked a width cap (the height scales by the same ratio, never cropped), then writes a JPG at the encoder quality you set. That one pass is what actually runs: convert <file> -resize <w>x -quality <q> out.jpg.

Both byte counts are measured: the upload's file size comes from its own stat and pixel size from identify, and the result's from the freshly written file. The saving percentage on the page is simply 1 minus compressed divided by original, so it is honest about files that grow.

The output is always a JPG, because that is the format with a real quality dial: files already smaller than that at your settings may end up bigger, which is reported rather than hidden. Any transparency the image carried is flattened when the JPG is written.

Questions about Image Compressor

Why is my PNG sometimes bigger after compressing?

PNG only beats JPG when the pixels are flat colours or text. Noisy photos always shrink; images that grow back are reported with a negative saving so nothing is hidden.

Does the width setting crop the image?

No. It caps the width and scales the height by the same ratio, keeping the whole picture, aspect intact.

Can I pick a quality that keeps detail?

Start at 85-90 for photos; 70 is usually fine for web posts. The card showing what changed tells you exactly how much room the trade-off saved.

Is the compressed file stored on the server long?

It is written once for the download link and rotated out shortly after, like every other file on this site.

Bookmark and homescreen