Extension proposal: thumbnail generator #256
Description
Have a content selector (like in the "chat with your content" app), load it in an iframe, set to the preferred aspect ratio for our thumbnails. Allows you to click on stuff and get the state of the app in the iframe to whatever you want to take an image of, then you press the camera button, which takes a screenshot of the iframe and then pops it up in a modal for you to review. Options there are "retake", which basically cancels out so you can adjust and take it again, or "save", which makes the appropriate Connect API call to set the image as the content item's thumbnail.
(This would also help us generate the thumbnail/preview images we should be including in the gallery feed.)