Compress an Image to Under 30 KB
A 30 KB ceiling, reached by searching quality rather than guessing it.
Who asks for a 30 KB limit
Examination application portals, forum avatars, chat stickers and small product thumbnails.
What 30 KB buys you in pixels
A workable ceiling for a 30 KB photograph is around 520 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 30 KB |
|---|---|
| Under 312 px | Comfortable — the quality search will settle in the high end of the range |
| 312–520 px | Workable — expect mid-range quality, check gradients for banding |
| Over 780 px | Resize down first, or the target cannot be met without visible damage |
30 KB is comfortable for anything under about 520 pixels wide. Above that, expect visible blocking in skies, skin and other smooth gradients.
Comfortable up to about half a megapixel
Thirty kilobytes sits at the point where searching quality alone usually succeeds, provided the image is under roughly 520 pixels on the long edge. Beyond that the search has to drop below quality 40, and blocking appears first in smooth areas and second as ringing around hard edges. Chat stickers and forum avatars are almost always already smaller than this before you begin.
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 30 KB.
- Let the quality search run — it reports the quality level it settled on.
- Check the resulting file is at or under 30 KB, then download.
Worth knowing
- Target 30 KB permits roughly 520 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 30 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.