Compress an image to 20 KB
Squeeze a photo under a 20 KB limit for older exam and government portals, with automatic resizing when quality alone cannot get there.
- Runs in your browser
- Files are never uploaded
- Free, no account
1 KB = 1024 bytes, the same arithmetic your operating system uses.
Only kicks in when quality 5 still overshoots.
20 KB is a very small budget
For scale: this sentence, as plain text, is about 80 bytes. Twenty kilobytes is 20,480 of them, and a photograph has to encode every visible detail into that. It is a limit set by form-processing systems written for dial-up-era storage — most commonly exam boards, recruitment portals and government e-services — and it is achievable, but only if you understand what has to give.
What fits
| Content | Realistic at 20 KB | Notes |
|---|---|---|
| Scanned signature on white | Easy, even at 800 px wide | Mostly flat white; compresses enormously |
| Passport-style headshot, plain wall | 300 × 400 px, quality 55–70 | The intended use of most 20 KB limits |
| Document scan, text only | Legible up to about 900 px wide | Grayscale it first if the tool allows |
| Outdoor snapshot | 250 × 350 px, visibly soft | Crop tightly or accept the softness |
| Screenshot with fine text | Not really | Text needs sharp edges JPEG cannot afford here |
The single most effective move: crop
At this size the encoder's problem is pixel count, not cleverness. A 3000 × 4000 photo has 12 million pixels to describe; cropping to just the head and shoulders might leave 600,000. That is a twentyfold reduction in what has to be encoded, and it buys back a huge amount of quality at the same byte count. Crop first with Crop Image, then come back here.
How the search behaves at extreme targets
The tool first binary-searches the JPEG quality at full resolution. At a 20 KB target that will usually fail even at quality 5, so it moves to the second pass and searches the scale factor instead, resampling with a Lanczos3 filter and re-encoding at a fixed mid quality. Fixing quality and searching size is the right way round: an image that is small and cleanly encoded looks far better than one at full size smeared into blocks. The result card lists every attempt so you can see precisely where it landed.
Format matters more than usual here
- WebP holds roughly a third more detail than JPEG at 20 KB. If the portal accepts
.webp, use it. - JPEG is the safe default and what nearly every form expects.
- PNG is a poor choice for photos here — it is lossless, so the only lever is size, and a 20 KB PNG photo will be tiny. It is, however, the best choice for a signature or a line drawing, which compress losslessly to almost nothing.
Common 20 KB requirements
Indian competitive-exam portals are the most familiar source: a photograph between 20 and 50 KB and a signature between 10 and 20 KB, with fixed pixel dimensions on top. Where a range is given, aim for the top of it — the largest allowed file is the clearest one you can submit. Where pixel dimensions are also specified, set the width cap first so the search works within them rather than fighting them.
What not to do
Do not run the output back through the tool a second time. Each JPEG generation re-quantises coefficients that were already rounded, so errors compound quickly — a file compressed twice to 20 KB looks considerably worse than the same original compressed once. If the result is not good enough, go back to your highest-quality original, crop harder, and try again.
Other targets
50 KB · 100 KB · 200 KB · any target you type.
Questions
Can a photograph really fit in 20 KB?
Only if it is small in pixels. A 20 KB budget realistically buys around 300 × 400 pixels of photographic detail at a usable quality, which is why the tool falls back to resizing. Signatures and scanned documents fit far more easily because they are mostly flat white.
The result looks blocky — what can I do?
Crop tightly before compressing. Every pixel you remove is a pixel the encoder does not have to spend bits on, so a tight crop at 20 KB looks dramatically better than a full scene squeezed to the same size.
Which format is best at this size?
WebP, by a wide margin — it typically holds 25–35% more detail than JPEG at the same tiny byte count. Use JPEG only if the portal explicitly demands .jpg.
Is the aspect ratio preserved when it resizes?
Always. The resize search scales width and height by the same factor, so nothing is stretched.