Attach pictures to a reply email
On a MacBook Air want to send a picture in a reply email
In Mail on your Mac open the Mail you want to reply to, then click the Reply button.
When the panel to compose a reply opens, click the Photo Browser in the toolbar of the window, then click "Photos".
Now you can browse your Photos Library from Mail.
It will only work, if you are using the Mail.app as your default mailer.