Hi - I'm happy to help with your Mac issue. Please remember to Accept when we are completely finished and you are satisfied with my answer.
Highlight the picture/pictures you want to send. Click on the Share icon on the lower right corner at the bottom of the screen. A drop down menu will be revealed when you click on this icon and one of the items is email. When selected, an email form will appear with the pictures attached - ready for you to address and add comments if you wish.
Thank you for responding. What you suggest I have already done and thus was able to send the necessary photos with an e-mail. What I want to do, however, (as indicated in the "Already Tried" note in the original question) is to send the photos as an actual attachment to the e-mail (to be opened by the recipient separately) or to place the photos at the end of the e-mail instead of at the beginning. I shall appreciate your help.
If you want to attach it - export the pictures from iPhoto as jpeg files to a convenient location on your Desktop. For example create a folder on the desktop called photo export and send the pix you want to send to it. Open a new email and address it. Create whatever messages you wish and then click Attach. Navigate using the open file dialogue to the folder you created. Select the files you want to send by using shift-click or command-click as appropriate, and click OK then send the email.