Want to share your blog article on Facebook but it's using the wrong image? don't worry you can force a post image on your blog articles that will be used if the wrong image, or no image at all, is being picked up.
First you want to edit your blog article, so go to Content > Blog. Now choose the blog article you want to set the post image for.
Once you are in the edit screen then go to the social tab, you will find a post image field that you can set an image for, just click on the yellow folder icon to open the file manager where you can choose an image or upload a new one.
When you have added your image just click save.
If after you have done this Facebook still isn't using the correct image it's probably because Facebook has cached your page and is using old data that it has stored, so you will need to tell Facebook that the page needs updating. To do this go to the Facebook Debugger tool (https://developers.facebook.com/tools/debug/) and enter your URL of your blog article and click the Debug button. This will force Facebook to reload your page and obtain the correct image for your blog article.