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 JPEG quality factor steps down until the file fits. The output is still a JPG and still opens anywhere.

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.

Getting a photograph down to 100 KB

1. 1

   Decide the pixel dimensions before the quality

   A 4000 px wide frame forced into 100 KB at full width has nowhere to go but the quality factor. Bring the long edge to around 1200 px and the same budget buys a far cleaner picture.

2. 2

   Start from the camera file

   JPEG throws information away every time it is written, and those losses stack. Work from what came off the phone or the camera rather than a copy a chat app has already shrunk.

3. 3

   Judge it at the size it will appear

   An image destined for a 700 px column should be assessed in a 700 px column. Blown up on a large screen it will look worse than anyone visiting the page will ever see it.

Why 100 KB is the size most photographs should end up at

Two unrelated jobs land on this number. An image inside an article has to earn its weight against page speed, and 100 KB is about the most a single photograph can take before a reader on a slow connection notices. Separately, a great many application forms that ask for an identity photograph set their ceiling right here. Both cases want the same file.

What 100 KB actually looks like

A 4000x3000 photograph weighing 3.4 MB comes back at 99 KB. The whole frame is kept, with the long edge brought down and the quality factor settling at roughly 75 to 80 once the dimensions are near 1200 px.

In that band the losses are real and hidden. Ringing around hard boundaries and faint mottling in even-toned areas are present in the data and invisible to the eye at ordinary viewing distance. This is the tightest target where that stays reliably true of a full frame.

Forms that cap an identity photograph at 100 KB

Photograph fields on application forms very often stop at 100 KB, and a good number of them also refuse a file that is too small, on the grounds that the resolution must be inadequate. Landing in the eighties or low nineties of kilobytes keeps you clear of both edges.

These validators read the file as submitted, so the number has to be under the stated cap on the copy you actually attach. Where the form also states pixel dimensions, satisfy those first and let the file size fall out of them.

When to pick a different number

If the photograph is the reason somebody is on the page rather than decoration beside the text, use the 150 KB target instead. The same 3.4 MB source lands at 145 KB there, and woven cloth, foliage and skin gradients hold together noticeably better.

If the image will only ever appear as a small square in a list or a grid, 100 KB is more than it can show at that display size. Half the budget does the same work, so the 50 KB page is the right one to use.

Questions people actually ask about this