It probably is that the server on the other end is mis-configured and is not declaring "image/jpeg" for files that end in ".jpeg". I would guess it is getting a content-type of "apllication/x-bin" or something like that. This is actually what Safari (and all other web browsers) is supposed to do, but InternetExplorer ignores this header (in an unpredictable manner) and guesses what the content is. This may look like a good behavior, but it is bad for two reasons: it masks the problem so that deb admins don't correct their servers, and every version of IE has different rules on what it ignores and how it decides what something is creating a minefield for people who are trying to use the system for things it was designed for.