Facebook doesn't allow you to customize a link image since 2017, unless it's a link from your own website and you've gone through FB's verification process.
For populating the link thumbnail, Facebook can only use what the website (Constant Contact) has designated as the og:image, which on Constant Contact appears to be the first image/header image by default. This can be seen by entering a Sent campaign's Email Link URL into Facebook's Sharing Debugger.
So, I want to specify, in Constant Contact, which image gets used as the thumbnail (og:image) when an Email Link is shared on social media. This is possible to customize on , for example, before a blast is sent. I'm assuming this functionality isn't available on Constant Contact?
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