Apple Mail not to include attachments? When I send an email from gmail.com, the attachments I add aren't included in the (rich text/html) email. However, if I attach images to an email via Mail all the images (videos as well) are included in the message.

I would like to disable this behavior, how can I do that? 

One is sent from gmail.com another is from Apple Mail (mail.app):
Both (gmail and apple) treat attachments differently. 
If you right click the PDF or Word document you should be able to choose from the menu, show as icon.

If you want to permanently show the attachments as icons in Apple Mail, close Apple Mail, open Terminal and issue the following command

defaults write com.apple.mail DisableInlineAttachmentViewing -bool yes


If you want to undo what you just did-
Close Apple Mail, open Terminal, copy and paste the following command

defaults delete com.apple.mail DisableInlineAttachmentViewing