I’m not creating new pages. I’m creating new posts. My posts have an image at or near the top. When I click on “home” in two of the blogs, the same image shows up with the excerpts there, but not in the other two. The images appeared in the blogs where nothing was checked under “featured image.” So I unchecked the box on the other two, thinking the images would show on the home page after the change. I have not defined featured images for posts.
There is a picture of a building here: http://sustainingourworld.com/2016/02/04/leed-certification-for-your-green-home/ that also appears with the excerpt here http://sustainingourworld.com
There is a picture of a young child with a violin here: http://music.allpurposeguru.com/2016/01/romanian-rhapsody-no-1-by-george-enescu/ but not on the excerpt here http://music.allpurposeguru.com/ There are no pictures with any excerpts for this blog.
It stands to reason that if all the settings are the same, all the blogs should behave the same. They’re not, and I don’t know where else to look for what might be different. And I have checked using two browsers.