You can embed your image into your e-mail. Store the image you want to use in OneDrive and then use the action Get file content using path action. Follow this with an Initialize variable action of String type. You can name the variable anything you want, such as embedded image. Then set the default value as:

Use the expression builder to generate the two body.$content... expressions above. The first expression is:
body('Get_file_content_using_path')['body']['$content-type']
And the second expression is:
body('Get_file_content_using_path')['body']['$content']
When you first add them, they will look like regular expressions in the variable action:

But once you run the flow they'll have the OneDrive icon as above. And of course, update the alt, width and height values to correspond to your image.
The put your e-mail message in HTML mode and insert the variable where you want your image placed.