30 KB is a common ceiling for signatures and for photos on state portals. It is roomy for a signature and enough for a clear passport-style photo at a few hundred pixels wide. If your photo comes out blocky at 30 KB, the pixel size is probably still too large — set the dimensions from your notification and the quality will go back up. The cap is 30,000 bytes, safe for portals using either definition of a kilobyte.

New to KB limits? Read the full guide on the compress to 50 KB page: how the compression works, 1,000 vs 1,024 bytes, min–max ranges and keeping photos sharp.