Why doesn't Outlook consistently show pictures in my messages?

This one's tough because there are so many variables that aren't specified.

First possibility: is your home mail client the same as the one you're running at work? Quite possible that's how it handles embedded pictures, espectially if the message came directly from the same source (i.e. not forwarded) and the pictures show up as attachments.

Or, perhaps your home mail client is protecting you from embedded pictures? Check for security settings: Outlook, Outlook Express, Thunderbird and others now don't show pictures by default. If that's the case, then you might simply need to disable that feature or perhaps add the sender to a "safe senders" list.

Third possibility, the one I think is most probable, is that you're forwarded the mail from work to home? If so, the mail client at work either just does it that way, or you received the mail as HTML or Rich Text Format, and it ends up being forwarded as "plaintext". The later can't include pictures within messages, hence the images would have to be converted to attachments.

But that's all guessing. It boils down to the email clients involved at this point. Sorry I can't be of more help.