🗜️ Image Compressor

Reduce a JPEG or WebP image's file size with an adjustable quality slider. Compression happens locally in your browser — nothing is uploaded.

Choose an image

Quality (%)

Format

JPEG WebP

What compressing does here

Your file is decoded, redrawn onto a canvas at its exact original dimensions, and re-encoded as JPEG or WebP at the quality you set. Everything happens in the browser - the picture is never uploaded, and the tool works offline. Pixel dimensions are untouched; only the encoder's quality changes.

reduction % = (1 - compressed bytes / original bytes) × 100
4.00 MB in, 820 KB out  ->  80% smaller

If the result comes out bigger than the source, the reduction is reported as 0% rather than a negative number.

Picking a quality

75 to 85 is the usual sweet spot for photographs. Below about 60, flat areas like sky start to show blocky banding.
WebP is roughly 25-30% smaller than JPEG at matching quality and keeps transparency, which JPEG cannot.
Quality 100 is still lossy. It reduces the discard, it does not switch the encoder off.

This is a re-encode, not a repack: a JPEG is decoded and compressed again, so its losses compound. Re-compressing the same file over and over degrades it. The canvas also drops EXIF and ICC data, so camera details, date, GPS and any wide-gamut color profile are gone from the download.

Frequently asked questions

Does compressing an image lose quality?

Yes. JPEG and WebP both throw away detail the eye is poor at noticing, and because the original is decoded and encoded afresh you are stacking a second round of loss on the first. Keep your master file.

Why did my PNG's transparent background turn black?

JPEG has no alpha channel, so transparent pixels are flattened when the canvas is exported. Choose WebP instead, which keeps transparency and usually compresses better anyway.

It says compression failed on my phone - why?

Mobile browsers cap canvas area, roughly 16 million pixels on recent iPhones and less on older devices. A 50-megapixel photo exceeds that and the export returns nothing. Shrink the picture first with the Image Resizer.