A government, exam or job portal rejects your upload for being 20 KB too big, and the apps that fix it want your photo on their server and your eyes on their ads. This one does the shrinking inside your browser tab. The photo never leaves your device.
Every portal sets its own limits, so read them on the portal’s upload page and type the numbers here - the presets are only common sizes, not any one portal’s rules. JPG shrinks by quality and dimensions; PNG stays exact and can only shrink by dimensions, so very small targets may be unreachable for a detailed PNG, and this tool will say so instead of pretending. iPhone HEIC photos are not supported - convert the picture to a JPG or PNG first, then pick that copy.