Why don't photos sent in Mac Mail arrive as attachments?

I need to be able to send photos via email as attachments that can be opened and downloaded by clients or associates. Two PC based clients tell me that the photos are embedded in the body of the email, and there is no way to open or save them as attachments.I work in simple text, which I was told would simplify things, but the results are spotty at best.

I would be grateful for any suggestions.

Thank you

M Crisina