A WordPress plugin that automatically sets an image as the featured image at the same time as it is inserted into the post content.
When activated, this plugin adds a new button next to the "Insert into Post" button in the media manager modal. When clicked, this button will insert your selected media and then, if you have selected an image, set that image as the post's featured image. It is possible to select multiple media items to insert, so this plugin will set the last image in the set as the featured image.
After defries posted a tweet about this issue, I set out to solve it.