The picture you saw in the previous post was hoovered up from one of Gerard Van der Leun’s omnibus posts. In that capacity, it occupied something like 56,349 bytes, fairly modest for a JPEG these days. It was also a hair too wide for this format, so I trimmed it back to 480 x 584, which came to 44,386 bytes. Looked okay, but maybe too much white space. A little off the sides, a slight bit of resizing, and the final version was 480 x 577 — and somehow, still, 44,386 bytes.
Now nothing in the JPEG spec says that a smaller version has to occupy less disk space; but nothing prepares you for the smaller version that occupies exactly the same disk space.