Compress PNG to 100KB
Compress PNG to 100KB online. Reduce your PNG file to around 100KB for email, uploads and forms, free, fast, no watermark.
PNG files · up to 50 MB each · 100 MB with a free account
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Checking files and selected compression settings.
This page stops at 50 MB and one file per run. Pro compresses files up to 1 GB and a full batch in one go, with a priority queue.
What this tool does
Set 100 KB as the target and the engine works down to it in steps, stopping at the first result that fits rather than padding the file back out.
The colour palette is reduced first, then DEFLATE is applied to what is left. Transparency survives: an alpha channel goes in and comes out.
Files are processed on our servers, not in your browser. The upload and the result are both permanently deleted within 1 hour, no backups and no copies kept.
No watermark, and no account needed to use it. 5 files a day at up to 50 MB each, sent singly or together; signing in is free and raises each file to 100 MB.
Working a screen capture down to 100 KB
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1
Crop to the part you are pointing at
A capture of the whole desktop spends most of its allowance on window chrome and empty panels. Crop to the dialog or the menu the reader needs and the pixels that remain get the entire budget instead of a slice of it.
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2
Let the target choose the palette
Type 100 KB in and leave the colour decisions alone. Hand exporting to an 8 or 16 colour palette means guessing, and the guess is usually wrong in one direction or the other.
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3
Inspect the soft areas
Title bars, drop shadows, translucent sidebars and button fills are where a reduced palette announces itself. Labels and borders come through at this target far more dependably than smooth shading does.
What 100 KB buys on a screenshot
Two quite different jobs land on 100 KB. Digital signature uploads for banking KYC, CAMS and KFin onboarding and demat account opening state it as a hard cap. Documentation screenshots end up there because a help page carrying a dozen images has to stay quick. The first is a rule you cannot argue with. The second is a habit, and it is worth knowing what it costs before you adopt it.
Fewer colours, not softer pixels
PNG is lossless by definition, so there is no quality dial to turn down. The two levers available are the colour palette and the pixel count. Moving a file from 24 bit truecolour to an indexed 256 colour palette, or down again to 16 colours, removes 40 to 70 percent of the weight without blurring a single edge.
That is why a flat interface capture takes this target so easily. A panel of solid fills and black text holds a few dozen distinct colours, and an indexed palette stores all of them exactly. A 1600x1600 flat colour logo measured here is already 20 KB before anything happens to it, and asking for 100 KB leaves it untouched.
The point where the width starts going instead
When the palette alone cannot reach the cap, pixels go. A 2560x1440 screenshot of 1.7 MB measured here comes back at 99 KB, shrunk to 837x470. That is a third of the original width, and on a dense screen full of 11 point interface text it is the edge of readable.
Gradients are the other casualty, and they are the reason this happens. A macOS translucent sidebar or a dark mode panel with subtle shading contains thousands of near identical colours. An indexed palette cannot hold them, so the encoder either steps them into visible bands or scatters dots to fake the difference, and then drops resolution because neither saved enough.
Cases where 100 KB is the wrong request
If the image is a photograph that happens to be sitting in a PNG file, stop. Lossy WebP at 100 KB looks about as good as a PNG of 400 KB, and a JPG of the same photograph reaches 99 KB with the full 1920 px width intact. Converting the format beats any amount of PNG compression on photographic content.
If nothing is imposing the cap and the picture is a full window screenshot, use the 200 KB target instead. The same measured file holds 1246x701 there against 837x470 here, which is the difference between a reader squinting and a reader reading. Reserve 100 KB for signature scans, icons and cropped details.
Questions people actually ask about this
The KYC form rejected my signature even though it is under 100 KB. Why?
Most of these forms enforce a floor as well as a ceiling, and reject anything tiny as resolution too low. They also tend to specify pixel dimensions separately from file size. Aim for the 80 to 95 KB band rather than the smallest file you can produce, and read the dimension requirement on the form.
Why did my capture come back narrower than I uploaded it?
Because palette reduction ran out of room. The colour count is tried first, and only when that cannot reach the cap does the pixel grid shrink. At a 50 KB target the measured 2560x1440 screenshot drops all the way to 575x323; at 100 KB it keeps 837x470.
There are steps across the gradient in my screenshot now. Can I stop that?
Not at this target, if the gradient is large. Either recapture the interface in a light theme with flat fills, or move to the 200 KB target, which gives the palette enough entries to render the shading smoothly.
The form will only accept PNG and my image is a photo. What do I do?
Downscale it yourself first, to roughly 800 px on the long edge, then compress. You are working against the format here rather than with it, so expect a visibly worse result than the same photograph would give you as a JPG at the identical cap.