Mailchimp video merge tag: the thumbnail links out, so pick it well

In a Mailchimp email, a video merge tag does not play the video in the inbox: it inserts a thumbnail image, and the thumbnail's click target is a URL you control (the default goes to the video service's page). So the frame you pick is the entire pitch. Sume's video frames extracts stills from a clip at times you name, so you can compare candidates before you send.

Mailchimp's page is Add and Track Videos with Wistia, read 2026-10-03. It covers Wistia specifically, and mentions video merge tags for other services; it does not describe what every inbox displays, so test before sending, as the page itself advises.

What does Mailchimp's page say about the thumbnail?

Mailchimp's page does not say Mailchimp hosts or plays video itself. The Sume angle is the still, and the page the click lands on.

• Video merge tags insert content from video services into an email; for Wistia you copy the merge tag from Wistia and paste it into the body of the email.
• You can adjust the settings of the video's thumbnail image.
• The default thumbnail setting is Links to URL, which sends the viewer to the Wistia Media Page, and it can be set to link elsewhere.
• Wistia tracks views, and Mailchimp tells you to test the merge tag before you send.

How do I pick the poster frame?

Video frames takes one clip hosted on media.sume.com and exactly one of at[] (1 to 24 times in seconds) or fps, and returns durable image artifacts at the source size unless you set max_edge (16 to 2160). It is always asynchronous: the submit returns 202, and you read the result from GET /v1/video-frames/:id. A time at or past the clip's duration fails as frame_time_out_of_range.

Ask for six candidates across the first 12 seconds and choose by eye. A frame with a clear face or product and empty space reads better as a thumbnail than a mid-motion blur.

curl -X POST https://api.sume.com/v1/video-frames \
  -H "Authorization: Bearer $SUME_API_KEY" \
  -H "Content-Type: application/json" \
  -H "Idempotency-Key: mailchimp-poster-001" \
  -d '{
    "video_url": "https://media.sume.com/artifacts/artf_demo/issue-video.mp4",
    "at": [0.5, 2, 4, 6, 8, 11],
    "format": "jpeg",
    "max_edge": 1200
  }'

Where should the thumbnail link?

Because the setting can point elsewhere, send the click to a page that plays the video at once rather than a generic gallery. A landing page that autoplays removes a step between the tap and the content. The page that hosts the video needs the file on a host you control; the Mailchimp page above covers Wistia, and says nothing about files hosted on Sume's media domain.

Sume gives you the MP4 and the still. It does not host a player page for email, so link to your own page or video host.

What if the frame needs cropping?

A 16:9 or 9:16 frame may not suit the email column. Video filter can crop the clip with fractions of the frame (x, y, width, height) before you extract stills, and POST /v1/video-filter/check validates the program for free. Crop first, extract second, so the poster matches the video the viewer clicks into.