can you explain further??  you want an image from the first post in a topic to appear in every post in that topic?  the wp featured post is only valid for that one post and does not scan multiple posts.. of course you can select the same image in another wp post, but its an overt, non automatic action..

in sp, you can upload an image as the first thing to any post already with the file uploader…

perhaps I am not understanding your use case…

Sorry for not explaining in more details earlier. Please view the image below as the saying goes a picture worth a thousand words. 

In a forum view I would like to show image thumbnail of the related post’s first image if available. Or add an image url as feature image that will show next to the forum title.

ah, didnt realize you meant on forum view…  lol, guess if I had read the title…

we did have one person request something similar a few years back, but this is only the second request..  so kind of low priority…  but I have made sure its captured on our list…