Compress JPG to 100KB

A 100 KB ceiling is almost never a technical constraint — it is an administrative one. Government application portals, university admission systems, visa and passport forms, and older recruitment platforms commonly cap photo uploads at 100 KB because the limit was set when storage and bandwidth were expensive, and nobody has revisited it since. The form rejects the file without explaining what to change, which is usually why people end up looking for a tool.

Because the limit is arbitrary rather than derived from image quality, the sensible approach is to meet it exactly rather than overshoot. Compressing to 40 KB when 100 KB is allowed throws away detail you were permitted to keep, and on an identity photo that detail is the difference between a clear face and a blocky one that gets the application returned.

A modern phone photo is between 2 MB and 8 MB, so reaching 100 KB means discarding roughly 95–99% of the file. Quality reduction alone cannot do that cleanly: forcing a 12-megapixel image under 100 KB with the quality slider lands somewhere around quality 20, where block artefacts are obvious across the whole frame.

Reducing dimensions first is what makes it work. Most forms that cap at 100 KB also specify pixel dimensions — often something like 600×800 for a portrait photograph. Resizing to those dimensions before compressing usually brings the file close to the limit on its own, leaving the quality setting to make a small final adjustment rather than doing all the work. If the form specifies no dimensions, capping the longest edge around 1200px is a reliable starting point.