100KB is the most commonly demanded image limit on the internet, and almost nobody who demands it explains how to meet it. Job application portals, university admissions systems, government forms, visa applications and bank onboarding pages all converge on this number, reject anything larger, and offer no help beyond the error message.
Why a fixed quality setting will not do it
The obvious approach — save at quality 60 and hope — fails because the relationship between JPEG quality and file size depends entirely on the picture. A plain headshot against a white background at quality 60 might be 40KB. A photograph of a market street at the same setting could be 400KB. There is no single number that works for every image.
So this tool searches instead. It encodes the image, measures the result, and adjusts — halving the range each time, about a dozen times over. That converges on the highest quality setting that still fits under 100KB, which is the best-looking version of your image that meets the limit. Guessing gets you either a rejected file or one that looks worse than it needed to.
Where 100KB usually lands
- A passport-style headshot at 600×800: comfortable, usually quality 80 or above, visually indistinguishable from the original.
- A phone photo at full resolution: tight. Expect the tool to reduce the dimensions, because 12 megapixels cannot be described in 100KB at any quality.
- A screenshot of a document: usually fine, though small text may soften — see the note on that below.
- A detailed landscape or a crowd scene: hardest, since fine detail everywhere is exactly what costs bytes.
When the dimensions have to come down
If quality alone cannot reach the target, the tool reduces the pixel dimensions in small steps and searches again, repeating until it fits. This is deliberate: a 4000-pixel-wide photo squeezed into 100KB by quality alone would be a blurry mess, whereas the same photo at 1200 pixels wide can look genuinely good at that size. When this happens you will see a note saying so, along with the dimensions it settled on.
A warning about document scans
If you are compressing a scanned certificate or ID for an application, check it is still readable before submitting. JPEG discards fine high-contrast detail first, which is precisely what small printed text is made of. If it comes out fuzzy, cropping away the empty margins before compressing usually helps more than anything else — fewer pixels to describe means more bytes available for the ones that matter.
Everything runs in this tab on your own device, which matters when the file is an identity document, a certificate or a bank form. No copy is created anywhere else.