Crop before you compress
Empty background costs bytes. Cropping tight on the subject leaves more of the size budget for the detail that matters.
Compress an image to 100 KB
100 KB is a common upload cap for ID documents, certificates and scanned proofs. Drop your photo in below — the target is already set to 100 KB, and everything runs inside this browser tab, so the image never leaves your device.
How to get a photo under 100 KB without it turning to mush
Match the required dimensions
Most forms cap both KB and pixels. Set the dimension preset here as well so a 100 KB file is not rejected for being the wrong shape.
Use JPG for photos
PNG stores photos far less efficiently. Choosing JPG output often reaches the target with visibly better quality.