Where can I find the setting to set a default blog post image, for users who don't add an image to a blog?

Hi Marie.Cassidy , currently there's no option to do that in the platform. Actually a shame because it looks bad if some posts have and some posts don't have a post image. We have had to code this in for multiple clients.

Actually there is an option for this. Pencil Icon > Manage Blog > Post Options: Default post image. 

Tom Paolucci And this would have to be done per application, correct? 

Tom Paolucci totally right, posted too fast. Not site-wide!

Thanks Tom. This helps a little, but the correction solution would be to have a site wide image.

136 Groups and Counting for me.

Thanks Lennert Fransen - My solution does not work site-wide, it would have to be managed for each blog implementation. 

Thanks Lennert Fransen - My solution does not work site-wide, it would have to be managed for each blog implementation.