I found the answer after wasting at least an hour searching. Finally I asked the support bot:
From the Substack post editor, click on Settings at the bottom of your draft post
In the social preview section, you'll see what your post will look like on social media and other public places
To select a different image from your post for the preview, hover over the thumbnail or click "Upload New"
To change the text, click the "edit" link or click on the box itself.
For best results, we recommend images be at least 420x300 pixels, though 1456x1048 pixels is optimal for social preview images (read more). The default social preview image is automatically the first image in your post, but you can customize it using the steps above (read more).
Can somebody please tell me how to add or change the thumbnail image in the article? Can't find the answer anywhere.
Substack thumbnail management is terrible. Fix this, please
I found the answer after wasting at least an hour searching. Finally I asked the support bot:
From the Substack post editor, click on Settings at the bottom of your draft post
In the social preview section, you'll see what your post will look like on social media and other public places
To select a different image from your post for the preview, hover over the thumbnail or click "Upload New"
To change the text, click the "edit" link or click on the box itself.
For best results, we recommend images be at least 420x300 pixels, though 1456x1048 pixels is optimal for social preview images (read more). The default social preview image is automatically the first image in your post, but you can customize it using the steps above (read more).
me three. I'd also like to know how to update the thumbnail image... (thank you for the article!)
I’d also like to know how to update the thumbnail image, where is it? Great article, thanks!