The offer has to be readable text

Answer The offer has to exist as readable text. RFC 2046 is the MIME document that names media types. text/plain and text/html are text. An image type is a picture. A solo ad whose only copy of the pitch sits in a picture has an offer that disappears when the picture does. Put the words where a mailbox can show them as words.

The note that started this: RFC 2046, MIME Part Two, Media Types, RFC 2046.

Yesterday's note said an image-only letter is still a message. Today is the choice inside that message. You are allowed to include a picture. You are not wise to let the picture be the only place the offer exists. If you buy solo ads, approve the text the platform will send, not the slide the designer emailed you.

Media types are labels. They tell the receiving software what a part is, so it can decide how to show it. A label of text means the bytes are characters. A label of image means the bytes are a picture that some other program has to draw. Software can refuse to draw it. A user can refuse. A security setting can refuse. The characters, if you included them, can still be shown. That difference is the whole creative decision.

What is the difference between a text part and an image part?

RFC 2046 assigns media types. A text/plain or text/html part is readable text. An image part is a picture. They travel in the same message and they fail in different ways.

Text fails when it is missing, misleading, or so cluttered that a person will not read it. Images fail when they are large, blocked, or hosted on a name that looks like last year's phish. Those are different outages. A message that carries the offer in text still says something during an image outage. A message that carries the offer only in the image says nothing, and the subject line has to do a job it was not sized for.

HTML is text with instructions. It is not a picture, even when designers treat the preview as one. The instructions can be ignored. A client can show the HTML as a simplified page, or it can prefer the plain part. If you wrote the offer in a heading style and nowhere else, you wrote it in a suggestion. Repeat it in a sentence.

• The plain-text part states the offer and the link.
• The HTML part states the same offer, not a different one.
• The image illustrates the offer and does not replace it.
• The subject line matches the text part.

Can the HTML part be the only place the offer appears?

It can, and it should not. HTML can be stripped, reformatted, or hidden behind an image. A plain sentence of the offer gives the reader something to read when the decoration does not survive.

Affiliate buyers are the usual offenders, because the swipe file arrived as a screenshot of a pretty email. The screenshot is a photograph of someone else's HTML. Your seller's platform will rebuild it. Buttons will move. A tracking link will replace the pretty one. If you never had the words in a form you can paste, you cannot check the rebuild. Read the text part after the platform assembles the draft, before the schedule locks.

A second reason is trust. Readers who have been burned learn to distrust a wall of art and a tiny line of legal type. The offer you would say out loud at a table is the offer that belongs in the text part. If you would be embarrassed to have that sentence next to the from-name, the picture was hiding a problem, not a design.

What should you approve before a solo ad goes out?

Approve the words, the link, and the identity of the sender. Do not approve a mockup in place of the text part. The mockup is not what every mailbox will show.

Three approvals. The words are the offer. The link is where the click goes, including the tracking wrapper if there is one. The identity is the from-name and the domain, which should already be on the quote from the first days of this month. A mockup can sit beside those three. It cannot stand in for them.

RFC 2046 is a labeling document. Use it as a label check. If the only part that contains the pitch is labeled as an image, send the creative back. The offer is a sentence. Sentences survive mail clients. Posters do not.