Composer blog elements - thubnail

Hi guys!

Can anyone tell me how to include thumbnail to composer (as in sample content)?
I installed c5 with sample content, then was playing with it a little bit, and one of things that I've done was, that I excluded Thumbnail image (in page type defaults) from composer. But when I included it back, it turned to regular image block, and don't open in image editor as it used to...
How to revert that?
And in general - how to add thumbnail, and header image as it is when we install sample content?

View Replies:
MysteriousCleon replied on at Permalink Reply
Really no one knows how to do that?