Compress an image to a size range

Because a very small file usually means a very compressed one, and the reviewer needs to be able to read the document or recognise the face. A minimum is a crude proxy for legibility. It is crude enough that a small, clean image can fail it while a large, blurry one passes - which is why this tool raises quality to reach the floor rather than inflating the file some other way.

No, and it never will. Appending meaningless bytes to a JPEG would satisfy any minimum instantly and add no image at all - the same dishonesty as grinding quality down to hit a maximum, which this engine also refuses. The only lever used is quality, upward, which means the file gets larger by keeping more of your photograph. If even the highest useful quality falls short, the page says so.

Whichever your own form states. No specific exam, agency or employer is named on this page, and that is deliberate rather than an oversight: those requirements are published per-form and per-year, often inside a PDF notification, and they change. A page that told you the requirement was 20 to 50 KB would eventually be confidently wrong for somebody, and the cost of being wrong is a rejected application.

Because signatures are wider than they are tall, and forms that specify an orientation almost always want that one. The option here crops to landscape if your scan is not already, which usually just trims empty paper. If your form asks for a specific pixel size instead, use the resizer first and then come back for the size band.

You are told, rather than given something that misses. Very small images sometimes cannot reach a minimum even at maximum quality, because there is no more detail in them to keep, and PNG cannot be tuned to a size at all because it is lossless. In both cases the page explains which end could not be met and hands you the closest result it managed.