A clean, small photo can compress below the minimum the form asks for. The tool then raises image detail step by step until the file lands inside the range. If it still cannot reach the minimum, it tells you, and the fix is to upload a sharper original taken at a higher resolution.

Phone cameras pick up paper shadow. Sign with a dark pen on plain white paper, shoot it in even daylight without a shadow falling across the page, and crop close to the signature itself.

Yes, if your browser can decode HEIC. Safari on iPhone handles it directly. On a desktop browser that cannot open HEIC, share the photo as JPG from your phone first.

No. The file is read by your browser, drawn onto a canvas and compressed locally. Nothing leaves your device, so the tool also works with a weak connection.

Some forms want your name and the date printed under your signature or photo. That tab draws both on a white strip, keeps the final image inside the exact pixel and KB limits, and gives you one JPG to upload.