This may not be related, but I remember IE putting a 1px whitespace under images that had a line feed after the IMG tag. Really weird, but was something that made me pull my hair out because "IT'S NOT SUPPOSED TO WORK THAT WAY!!!!"
Blasted IE.
e.g.
Code:
[img]image.png[/img]
That extra line feed after the image tag put a white space right under the image.