No, you can add attachments that can be referenced OR you can add images with a data URI.
As an attachment: Help formatting an image as an email attachment using Nodemailer - #5 by Steve-Mcl
As inline:
- How to send an image from mqtt in an email - #10 by Steve-Mcl
- Fetch image and send to email - #2 by Steve-Mcl
There are more (use the forum search for things like
email html image
etc)