Compress an Image to Under 10 KB
A 10 KB ceiling, reached by searching quality rather than guessing it.
Who asks for a 10 KB limit
Web thumbnails, favicons, email signature images, and a handful of government portals with an unusually tight cap.
What 10 KB buys you in pixels
A workable ceiling for a 10 KB photograph is around 320 pixels on the long edge at a quality that still looks like a photograph rather than a mosaic. That figure is empirical: it comes from how much high-frequency detail survives compression at that byte budget, and it moves up for images with large flat areas and down for images full of foliage, fabric or hair.
| Long edge | What to expect at 10 KB |
|---|---|
| Under 192 px | Comfortable — the quality search will settle in the high end of the range |
| 192–320 px | Workable — expect mid-range quality, check gradients for banding |
| Over 480 px | Resize down first, or the target cannot be met without visible damage |
At 10 KB you are past the point where quality selection alone will get you there. Crop or resize first — a 3000-pixel-wide photo cannot be squeezed into 10 KB at any quality that is still worth looking at.
At this ceiling you are fighting the format, not the setting
Ten kilobytes is roughly 80,000 bits for the entire picture. A single unbroken sky gradient can consume most of that at any quality setting, so the practical route is to cut the pixel count first: a 320-pixel image holds around 100,000 pixels, which is about 0.8 bits each at this budget. Dense foliage and photographs of text will not fit at all; flat logos and single-subject portraits will.
Why this runs in your browser
The file is read from your disk by the browser, decoded with the browser's own codecs, and re-encoded in this tab. No upload request is made, nothing is queued on a server, and closing the tab leaves no copy anywhere. You can verify this in the network panel while it works.
How to use it
- Drop the image on the drop zone.
- Set the target size to 10 KB.
- Let the quality search run — it reports the quality level it settled on.
- Check the resulting file is at or under 10 KB, then download.
Worth knowing
- Target 10 KB permits roughly 320 pixels on the long edge at photographic quality.
- The quality search encodes repeatedly and keeps the highest quality that fits.
- Image content, not just dimensions, determines how far the quality can be pushed.
- Switching to WebP at the same 10 KB budget usually looks visibly better than JPEG.
Limitations
- Very tight targets require resizing as well as compressing — compression alone has a floor.
- Downscaling permanently discards pixels; keep the original as your archive copy.
- Re-compressing an already-compressed file spends quality twice.
- Some portals also check pixel dimensions and file format, not just the byte count.