BLOG PHOTOS

When Dad began blogging I set up a basic account for him to get him started. I stuck on a baby photo of him and it appeared on his blog page, on his profile and was attached to all comments he made on others' blogs. Today, now he's getting more into blogging, he decided to change that photo for another of his personal favourites. He amended the photo URL in the profile, replacing the one I had chosen with the new one and saved. Now his photo appears on his profile, but no longer on his blog and no longer on his comments. Has he done something wrong? I can't find anything? Does anybody out there know?