I have a Google spreadsheet that contains recipient's names, emails, and a message that anonymous people have sent this Valentine's Day. I am aware of applications such as the various Mail Merges that allow one to send personalized messages. All of which that I have found, however, send in plaintext (at least in their free versions). In the Mail Merge add-ons I have used, I can't seem to include images either. I am also aware of scripts that can send HTML emails, but none that can send personalized emails automatically to a large number of people.
An example message I am looking for may just be something like a simple banner image, greeting (with variable name), and variable message, perhaps with everything centered.
The easiest way I can think of to achieve this is by sending an HTML email, so I'm looking for a way to retrieve spreadsheet values for a template HTML document to send the personalized messages.