Send files via iMessage with the Finder in OS X
How to use the Finder to send files on your Mac
Here's how you can use iMessage to send files from the Finder in OS X.
1. Open the Finder.
2. Find the file you want to send.
3. Right click it and move your cursor to the Share option.
4. Choose the Message option.
For more, see the original article at the link below.