unable to email multiple photes from my mac

Open a new mail message compose window; the window you use to send a mail message. Open Photos. Drag the photos you want from Photos app into the compose window. Send.

You can also use the photo browser tool in the compose window. If you don’t have that tool showing in your icons at the top of the compose window, control-click on the top bar of the compose window and use the customization feature to add the photo browser icon.