Auto set thumbnails of featured images

Auto post thumbnails of featured images in Wordpress is very useful when you are creating many records automatically, for example using some sort of feed.

You can use plugin called "Auto post thumbnail".
When you have actually installed it, don't update to 3.4.1 version - it's not working properly with new versions of Wordpress. Till the version 3.4.0 it's safe.

You can also run it for old post, choosing settings menu/auto post thumbnail

and clicking "Generate Thumbnails"

Then you'll see a progress bar:

To see featured images on the post list, you can use another plugin, called "Post list featured image"

and the effect of it's work: