If it's any indication on the informedness of the article:
In reality, an MMS is about one million times more data than a text message.
The payload of an SMS is 140 bytes. The MMS specification does not specify a limit, but providers often cap it at 300kb. Which, of course, is about 2000 times more.
Now, if an MMS had about a million times more data than a text message, that would make each message about 140 megabytes.
The article seems to have updated. It now reads "In reality, an MMS or email is anywhere from a thousand to a hundred thousand times more data than an SMS." Given that the previous paragraph says that it's an "email containing photo(s) and/or video(s)", that seems perfectly reasonable (it puts the range between ~140 KB and ~14 MB).
If that's the case, your sysadmin either needs to stop living in the past, or provide something more convenient than e-mail. Storage and LAN bandwidth are ridiculously cheap.
Stop living in the past? Sure. The Cloud is the new fad, everyone's talking about it. We have our company email managed in the cloud. LAN bandwidth and local storage has nothing to do with the bottlenecks in this system.
Now, if an MMS had about a million times more data than a text message, that would make each message about 140 megabytes.