Compress Image

Compressing an image means re-encoding its pixels with a codec that throws away detail your eye is unlikely to notice. This tool decodes each file into an offscreen canvas, optionally scales it down, and re-encodes it through the browser's built-in JPEG, WebP or PNG encoder at the quality level you picked. Because every one of those steps is a native browser API, the work happens on your own CPU — there is no upload, no queue, and no server that could keep a copy of your photos.

Two settings do the heavy lifting, and resizing is the more powerful of the two. A modern phone camera produces roughly 4000×3000 pixels. Almost nothing needs that: an email attachment, a website hero image or a WhatsApp photo is displayed at well under 2000 pixels wide. Capping the longest edge at 1920px removes about three quarters of the pixels before the encoder even starts, which usually cuts the file by 80–90% with no visible difference at normal viewing sizes.

Quality controls how aggressively the encoder discards fine detail within the pixels that remain. "Best quality" (90%) is essentially indistinguishable from the original. "Balanced" (75%) is the right default for anything shown on a screen. "Smallest file" (55%) starts to show soft edges around text and sharp contrast, so use it when hitting a size limit matters more than perfection.

Format choice matters too. PNG is lossless, which makes it excellent for logos, screenshots of text and anything with transparency — and a poor choice for photographs, where it can be several times larger than a JPEG of the same image. The Auto setting keeps small PNGs (likely icons and logos) as PNG and sends everything else to JPEG. WebP is typically 25–35% smaller than JPEG at matching quality and is supported by every current browser, so pick it when the images are destined for a website.

One honest limitation: an image that has already been compressed hard will not shrink much further, and re-encoding it costs a little more quality. If a file comes back showing "no gain", the original was already well optimised — keep it.