Compress image to 20 KB

A 20 KB cap turns up wherever a picture is shown small and loaded often: a profile avatar on a forum or gaming site, the little logo in an email signature, a favicon-sized thumbnail, or a chat sticker. At the sizes these appear — usually 100 to 300 pixels across — 20 KB holds more detail than the display can show, so a bigger file only slows the page for no visible gain.

Older board software such as phpBB and vBulletin still rejects avatars above roughly 20 KB, because a community with tens of thousands of members stores that many separate copies. Keeping each one tiny is how those sites hold their storage and bandwidth down, which is why the limit has outlasted faster home connections.

Twenty kilobytes is a tight budget, so the biggest lever is dimensions rather than quality alone. Crop the image to the square or circle it will actually display in before compressing — an avatar shown at 240×240 needs a small fraction of the data a full photo carries. From there the tool lowers JPG quality until the file lands under 20 KB.

Flat logos, cartoon avatars and simple graphics hold up well at this size; a detailed photograph pushed this small will soften, so keep the crop tight and expect fine texture such as hair or leaves to lose some bite. As a rough guide, a 240×240 JPG at quality 70 usually settles around 12 to 18 KB.

The resize and re-encode both happen locally on this page, and the finished file is handed straight back without touching a server. That still counts for something as everyday as an avatar, since your face or a personal logo stays on your own machine. There is no upload queue and no account to set up, so you can drop in a full set of avatars for a team and clear them in one pass, held up only by your device rather than a network connection.

It is worth confirming the final size before you submit, because the most common slip is uploading the original by accident instead of the compressed copy. After compressing, the tool shows the new size beside the image; download that file and use it, not the one straight from your camera roll.

When a site lists both a byte limit and pixel dimensions, hitting the 20 KB target here handles the first rule, and cropping to the stated width and height handles the second — the two are checked separately, so make sure you satisfy both before the form will accept the image.