Substack Social Preview Image Specs
Your link looks broken on Twitter? It is because your OG image is missing or the wrong size.
1
The Social Card
Substack looks for a **1200 x 630 px** image to use as the social preview card.
2
Settings
Go to Settings -> Publication Details -> Social Preview. Upload a specific image here; don't just rely on the first image in your post.
3
Text Safety
Keep text in the center. Twitter/X often crops the edges of the preview card on mobile.