When a form says "maximum 200 kB", most converters leave you adjusting a quality slider by hand until the file happens to fit. This one takes the limit and finds the best quality that still comes in under it.
It converts the image seven times, each time halving the search range between 5% and 98% quality, and keeps the highest setting whose result still fits. Seven rounds is enough for a 1% difference — closer than you can see. The converter then tells you which quality it settled on, so you know whether the limit forced a visible compromise.
Portals that impose this limit: passport and visa photo uploads, job application systems, driving licence renewals, and most university submission forms. The exact number differs per country and per form — that is why the limit is an input here rather than a fixed promise.
If there is no strict upload limit, choose the quality yourself with WebP to JPG. For screenshots, graphics or transparency, use the lossless WebP to PNG converter.