Reduce any image below 20KB entirely in your browser. Targets 18KB by default to give a safe margin under strict 20KB portal limits.
18KB
Default Target
Safe Margin
Under 20KB
Any Format
Input Support
Private
No Uploads
Drop image here to compress to 18KB
JPEG, PNG, WebP, AVIF, HEIC. All processing stays in your browser.
Default target is 18KB. If your portal requires a different limit, change the target size in the field above.
A 20KB ceiling is one of the strictest file size limits you will encounter on a form or portal. It most commonly appears on signature upload fields and legacy government systems that were built to serve users on very slow internet connections.
Digital signature uploads
Many online forms require a scanned signature image under 20KB. This is the most common real-world reason users encounter this limit, particularly on banking, legal and government forms.
Avatar and profile thumbnail fields
Older portal systems with fixed-size thumbnail slots often cap uploads at 20KB because the image is displayed at very small sizes and does not need high resolution.
Strict legacy government forms
Some state-level government portals in India, Bangladesh and other countries impose a 20KB ceiling on applicant photographs, particularly for older scholarship and subsidy application systems.
Low-bandwidth submission systems
Portals designed for rural or low-connectivity users sometimes enforce very tight file size limits across all uploaded assets to ensure the system remains accessible on slow connections.
20KB works out to roughly 160,000 bits for the entire image. Spread that across even a modest 800 by 600 photo and there's only a tiny fraction of a bit available per pixel. No amount of turning down a quality slider alone gets a real photo down to that budget, since the format still needs some minimum amount of information to describe each block of pixels no matter how aggressive the setting.
JPEG compresses in 8 by 8 pixel blocks, and even at the lowest usable quality setting, each block still needs a minimum number of bits to describe it. Once a source photo has more of these blocks than the target byte budget can support, quality alone runs out of room. The only way to shrink the file further at that point is reducing the actual pixel dimensions before compression, not pushing the quality number any lower.
A signature scan or a simple line drawing is mostly flat white background with a small amount of dark line data. JPEG's compression finds huge blocks of nearly identical pixels to describe efficiently, so a legible signature can genuinely fit under 20KB at its original dimensions without needing the aggressive downscaling a full photo would require to hit the same target.
The tool doesn't guess a single quality number and stop. It repeatedly tries different quality and dimension combinations, checks the resulting file size each time, and narrows in on the highest quality setting that still lands under your target. That's why the same 18KB target can produce very different-looking results depending on what's actually in the source image, a signature keeps its full size and stays sharp, while a busy photo gets both compressed and shrunk to make the same budget.
Forms and portals that impose a 20KB ceiling are typically legacy systems built for low-bandwidth environments, or fields designed for small image types such as signature scans and thumbnail avatars. The limit is enforced server-side, meaning your file must be strictly below 20KB before you attempt to submit. Files at exactly 20KB are often rejected because the system checks for less than, not less than or equal to.
When a portal specifies a maximum of 20KB, any file smaller than 20KB will pass. You do not need to hit exactly 20KB. This tool targets 18KB by default, leaving a safe 2KB margin so your file passes even if the portal measures file size differently or has a slightly stricter internal threshold.
It depends on the type of image. A scanned signature or simple line drawing compresses to under 20KB with very little quality loss because these images have low visual complexity. A full-colour photograph at 20KB will show visible compression and reduced dimensions, but will remain clear enough for identity verification and form submission purposes.
JPEG, PNG, WebP, AVIF and HEIC are all supported as input. The output is JPEG or WebP. For portal submissions, always choose JPEG as the output format. It is universally accepted by every upload system including older government and banking portals.
No. All compression runs entirely in your browser using JavaScript and the Canvas API. Your image never leaves your device at any point. You can verify this by disconnecting from the internet after the page loads. The tool will still compress and download your image successfully.
Yes. Even a small reduction from 22KB to under 20KB is handled correctly. The binary search algorithm finds the highest JPEG or WebP quality setting that produces a file below the target, so small reductions like this work just as reliably as large ones. The tool targets 18KB by default, so you will have a comfortable margin below the portal limit.
