Version:            (using KDE 4.2.0)
Installed from:    Gentoo Packages

KMail's Size column seems to be bogus. It is showing me sizes from 318 bytes to 4.8 KB. Taking the email I was looking for into question, KMail's Size column shows "716 B", but the actual message (as shown below the preview pane) is:

RE: SUBJECT            multipart/mixed         7bit                3.2 MiB
[-] body part          multipart/alternative   7bit               11.3 KiB
 |  |- internal part   plain text document     quoted-printable    1.3 KiB
 |  |- internal part   HTML document           quoted-printable   10.0 KiB
 |- filename.pdf       PDF document            base64              3.2 MiB