What 25 KB is good for
25 KB is a documentation size. PAN card applications, KYC submissions, and a number of banking portals settle on it because it is enough for a legible identity photograph while keeping their storage predictable across millions of uploads.
The margin over 20 KB matters more than it sounds. That extra 5 KB is roughly a 25% larger budget, which is often the difference between a portrait that looks acceptable and one where compression is visible around the eyes and hairline.