Your apply to each loop is looping based on the number of attachments in the SharePoint item. The image is one of those attachments. To send only one email move the Send an email action outside the loop and replace it with something that builds the attachments and body of the email as variables. Then use the variables outside the loop to send the email.
----------------------------------------------------------------------------------
If this Post helped you, please click "Does this answer your question" and give it a like to help others in the community find the answer too!
Paul Papanek Stork, MVP
Blog: https://www.dontpapanic.com/blog