Unwanted image in Blogspot post feeds

When I feed a number of my posts on blogspot (but not all of them) to Facebook, an unwanted image appears above the written text that I never included.

The image is one of the photos that appear in the right-hand column of my blog, but was never added to the post, nor even necessarily related to the topic.

How do I make sure these photos do not appear in the Facebook feeds and perhaps feeds to other social media or email?

Thanks!