Mac Mail reducing image size making it unreadable to the recipient
Ok - I figured this out, there are actually a number of options:


If you are using inline images, when you add an image, there is actually a drop down menu just below the from address which states "image size", use that to size the image accordingly.
If you switch off inline images:

defaults write com.apple.mail DisableInlineAttachmentViewing -bool YES


This will send the image in the current size.

Well, there we go!