In FileMaker, you can't add photos directly to the body of your email unless you install a plug in that adds that capability. You can send pictures as file attachment, but you can only attach one file to any email, so attaching multiple photos requires using one of two methods to produce a single file that contains all the photos. Either way, you'll need a table of records with a container field so that you can store each photo in a separate record:
Method 1: devise a list view layout for displaying the photos. Perform a find to pull up the photos you want to send on this layout and save it as a PDF so you or your script can attach this PDF file to the email.
Method 2: Save each photo as a PDF in a script that uses the append to existing file option to combine the separate photos into a single PDF for attachment.