It sounds like you are seeing this text instead of the image:
The problem may be that the markdown link that you are seeing is surrounded by HTML tags. Try opening the post’s editor by clicking its ‘edit’ icon:
Clicking the pencil icon will open the editor. Search for image text in the editor and check to see if it is surrounded in HTML tags. If it is, add an empty line between the opening HTML tag and the markdown link.
If this is the cause of the problem, you can find more details about it here: Fix broken images for posts created by the WP Discourse and RSS plugins.
Let us know if this doesn’t fix the problem for you.