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Byte budget · 100 KB ceiling
Compress an image to 100 KB
A hundred kilobytes is a generous budget. At a sensible width it is enough for a photograph that still looks properly sharp, which makes it the right target for email attachments, blog images and any content management system that grumbles at large uploads.
Result
What 100 KB actually buys you
As a rough guide, a photograph of ordinary complexity needs somewhere between one and two bits per pixel to look untroubled at normal viewing distance. Work backwards from 100 KB and that lands you at roughly half a megapixel, which is about 1000 × 500. Push to 1600 px wide and you are asking the encoder to work harder; it will manage, but flat areas like skies start to show faint banding.
Complexity matters as much as size. A photo of foliage or gravel is dense with detail and expensive to store. A product shot on a plain white background compresses beautifully and might land at 100 KB even at 2000 px wide. The readout below the preview tells you which situation you are in by reporting the quality value the search settled on. Anything above about 75% means you had room to spare.
Using it for a web page
If page speed is the goal, file size is only part of the story. A 100 KB JPEG served at
1200 px wide to a phone that only needs 400 px is still wasteful, because the browser has
to decode all those pixels. Export a couple of widths and let the browser choose with
srcset. And consider WebP, which typically gets you the same visual result
about 25% smaller — there is a converter for
that on this site.
Steps
- Drop the image in.
- Choose a width. This matters more than the ceiling for how good the result looks.
- Press Compress, then check the quality figure in the results table.
- If the quality figure came out low, either raise the ceiling or drop to a smaller width.
Common questions
Which is better, a smaller image at high quality or a bigger one at low quality?
For the same file size, a smaller image at high quality nearly always looks better. Compression artefacts are ugly in a way that a slightly lower resolution is not, because the eye reads blockiness and ringing as damage while it reads softness as distance. Below roughly 60% quality, prefer resizing.
Can I compress a PNG screenshot to 100 KB?
You can, but the output will be a JPEG, and JPEG is poor at the crisp text and flat colour that screenshots are made of. Text picks up a coloured fringe. For screenshots, resize the PNG or convert it to WebP instead, both of which keep edges clean.
Does compressing twice make it worse?
Yes. Every JPEG generation loses information permanently, and the losses stack. Always start from the original file rather than from a copy you compressed last week. If you need a different size, go back to the source.
Why is the result larger than 100 KB?
It should not be. If it is, the tool will say so in red: it means even the lowest quality setting at the width you picked exceeded the ceiling. Choose a narrower width and it will fit.
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