Annotate Attachments in Mail

Slowly but surely, Mail has transformed from a bare-bones app into a versatile message manager, and things only get better in Yosemite. If you want to highlight something on a photo, for example, you no longer need to do your work in an image editor first; after attaching it, click on the small arrow in the top-right corner of the photo and you’ll get a menu of editing options, including type, lines, shapes, and drawing tools.