Drop a signature or photo and get a JPG under 20 KB in seconds. The target is already set and nothing is uploaded.
A 20 KB limit is one of the smallest you will meet on online forms. It shows up most often for the signature box on exam, job, bank and scholarship forms, and sometimes for a thumb impression or a very small photo. A normal phone photo is 2 to 5 MB, which is 100 to 250 times too big. This page lets you compress image to 20KB online with the target already chosen: drop the file, wait a moment and download a JPG that fits. It is a 20KB image compressor that runs entirely in your browser, so your signature is never sent to a server. Below you can see exactly how it decides between quality and pixel size, what our own test photo looked like at 20 KB, how to handle forms that also give pixel dimensions, and what to do when a form says “10 KB to 20 KB”.
The tool works in three steps. First it opens your image and turns phone photos the right way up. Then, for big photos, it makes a small preview and saves it at 50% quality to estimate how many pixels can fit into 20 KB, so it does not waste time on a full-size photo that can never fit. Finally it searches: it saves the image at 92% quality, and if that is too big, at 50%, and then halves the gap seven times to find the highest quality that is still under 20,000 bytes. Only if 50% quality is still too big does it shrink the width and height again and repeat.
Worked example (measured). In our own Chrome test we used a 2000×3000 phone photo of 672.9 KB. At 20 KB the result was 19.8 KB, 337×505 pixels, quality 52%. The file became 34 times smaller, and only about 3% of the original pixels were kept. That is the honest picture of 20 KB: fine for a signature or a stamp-sized face photo, not for a photo someone will look at full-screen.
Drop, choose or paste (Ctrl+V) a signature scan, thumb impression or photo. You can add up to 30 images at once.
The 20 KB button is already pressed, so compression starts at once. Each row shows the new size, the pixel size and the quality used.
Click Download to save a file such as signature-20kb.jpg, or Download all (ZIP) when you added several images.
It searches JPG quality between 50% and 92% and keeps the highest value that still fits, instead of using one fixed setting for every image.
If 50% quality is still too big, the image is made smaller in pixels, only as much as needed to get under 20 KB.
20 KB means 20,000 bytes here, the stricter reading, so the file also passes forms that count 1 KB as 1024 bytes.
The image is processed in your own browser and never uploaded. Free, no sign-up, no watermark, no daily limit.
Signatures are the easiest images to fit into 20 KB because they are mostly plain white paper with a few dark lines. You get a much cleaner result if the original is clean:
A cropped signature often fits 20 KB at the full 92% quality without losing any pixels. The big 2000×3000 test photo above had to shrink to 337×505 only because it was a full camera photo full of detail.
Many forms give two rules at once, for example “signature 140×60 pixels, 10 KB to 20 KB”. The compressor only controls the file size, not exact pixels, so do it in this order:
If a form only says “width 160 pixels”, use Resize by “Width” instead; the height follows automatically and nothing is stretched. The resizer also has a “File size (KB)” mode that uses the same compression as this page, but it does not set pixels at the same time, so two steps are still the safe way.
File size grows with the number of pixels, so a smaller target leaves fewer of them. This chart shows the width our 2000×3000 test photo ended up with at each preset size. All four results came from the same photo.
| Image | Fits in 20 KB? | What to expect |
|---|---|---|
| Cropped signature on white paper | Yes, easily | Often fits at high quality with no pixel loss |
| Thumb impression | Usually yes | Clear if the print is dark on white paper |
| Small face photo for a form box | Yes, but soft | About 300-400 px wide; check if 50 KB is allowed |
| Full camera photo, group photo, landscape | Only by shrinking a lot | Visible blur when opened large |
| Screenshot with text | Depends on size | Crop to the part you need first |
There are two ways to count a kilobyte. The official SI meaning is 1 KB = 1000 bytes; the binary unit 1 KiB = 1024 bytes is what Windows File Explorer uses, even though it writes “KB”. A form can check either one. The tool always uses the smaller number, so a file that passes here passes both ways. At small sizes the difference is a real margin:
| Limit on the form | If KB = 1000 bytes | If KB = 1024 bytes | Tool aims under |
|---|---|---|---|
| 10 KB | 10,000 bytes | 10,240 bytes | 10,000 bytes |
| 20 KB | 20,000 bytes | 20,480 bytes | 20,000 bytes |
| Our 19.8 KB result | 19.8 KB | about 19.3 KB | passes both |
Windows shows file sizes in whole numbers and may round 19.3 up to “20 KB”. That does not mean the file is too big; the form checks the exact byte count.
A range has a lower end too. The compressor aims as close to the top as it can while staying under it, so a detailed photo lands just below 20 KB. Problems only appear in two cases:
JPG and JPEG are two names for the same format, so a form asking for “JPEG under 20 KB” accepts the file this page makes. The output is JPG unless you open More options and pick WebP; most government and exam sites do not accept WebP, so keep JPG for forms. If the form wants a PDF, compress here first, then use JPG to PDF with PDF size “Smaller file”. Keep the output as JPG, not WebP: a JPG made here is small, has no rotation data and fits inside the Smaller file size limit (longest side 1600 px), so it is placed in the PDF byte for byte, without being saved again. The PDF is about the size of your JPG plus roughly 1 KB per page. For a 20 KB PDF, a target of 19 KB leaves room for that overhead.
Not completely. Going from 600 KB to 20 KB means throwing away over 95% of the data, and some detail always goes with it. What you can control is where the loss happens. The tool will not go below 50% JPG quality, because below that photos turn blocky; it prefers a slightly smaller but clean picture. You help most by cropping: every pixel of empty background you remove is a pixel the signature or face can keep.
Open the page in Chrome, tap the box and pick the image from your gallery or files. The result goes to your Downloads folder.
Use Safari or Chrome and choose the photo from Photos or Files. iPhone HEIC photos open too; outside Safari a small converter loads the first time, still on your phone. The JPG is saved in the Files app.
Drag the file onto the box, or copy a screenshot and press Ctrl+V on the page. Photos taken sideways are turned upright automatically.
The size limit is strict: the tool checks the real byte count of every saved file and only returns a result over the limit when it says so with “couldn’t reach the target”. In our test the photo came out at 19.8 KB, 99% of the limit. Things to know:
Many 20 KB compressors use one fixed quality setting or ask you to move a slider and try again until the number looks right. This page does the trying for you. For each image it saves real JPG files at different qualities inside your browser and measures their exact size in bytes, then keeps the best one that fits. Because the work happens on your own device, nothing is uploaded: your signature, which is a sensitive thing to hand to a stranger, never leaves your phone or computer. Once the page has loaded, compression works even if your internet drops.
It is also honest about what it did. Every row shows the size before and after, the pixel size and the quality, and the Copy summary button copies those lines so you can keep them. If a target is impossible, it tells you rather than quietly giving you a bigger file. And if your file already fits, it leaves it alone instead of making it worse.
For each image we measure the pixel width and height (after turning it upright), the original file size, and the byte size of every test file the search creates. The result shows the final byte size, pixel size and quality. We do not measure how sharp or readable the result looks; there is no visual quality score, so always look at the result before you upload it. We do not check what a specific form requires, and we do not set pixel dimensions on this page. A newly saved file contains no camera details or location, because the browser writes a fresh JPG; a file kept as it is still has its original metadata, which remove EXIF data can strip.
| VidHaul | Typical upload-based sites | |
|---|---|---|
| Upload needed | No, it runs in your browser | Yes, the image goes to their server |
| How the size is reached | Highest quality that fits, measured in bytes | Often a fixed quality or a manual slider |
| KB counted as | 1000 bytes, passes both readings | Not always stated |
| Watermark | Never | Sometimes on free plans |
| Sign-up | Not needed | Sometimes needed for batches |
| Works offline after loading | Yes | No |
| Privacy | Signature never leaves your device | File is usually stored for a while |
Need a different size? The main image compressor has presets from 20 KB to 1 MB. For a sharper photo on the same form, see compress image to 100KB.
Only upload your signature to official forms you trust, and keep the original file somewhere safe.
Open this page and drop the image into the box. The 20 KB target is already set, so the result appears in a second or two; click Download to save it.
JPG is the default output, so the file you download is already a JPG (the same thing as JPEG) under 20 KB. WebP is only used if you choose it under More options.
Start with a sharp, well-lit original and crop away empty background before you compress. Then most of the 20 KB is spent on the part that matters, and the tool can keep more pixels.
Use the image resizer with Exact size first to get the pixel size the form asks for, then drop that file here. A small JPG that is already under 20 KB is kept as it is.
Yes. Type 10 in the Target size box. At 10 KB a signature usually stays readable, but a face photo will be very small or soft.
Compress the image here, then turn it into a PDF with the JPG to PDF tool and the Smaller file option. A compressed JPG goes into the PDF unchanged, so the PDF is about the JPG size plus roughly 1 KB.
Yes. It is free, needs no account, adds no watermark and works in Chrome, Edge, Safari and Firefox on phones and computers.
The image could not fit 20 KB even after lowering quality and pixel size. The tool gives you the smallest file it could make; crop the image tighter or start from a simpler picture.