Is it no longer possible to upload a custom thumbnail for your YouTube videos using the new YouTube "info and settings" panel in the video manager? I read articles saying click the "Upload thumbnail" button, but I see no such button (see screenshot):
YouTube Thumbnail – How to Upload a Custom YouTube Thumbnail
youtube
Best Answer
Regular user accounts are unable to upload custom thumbnails for their videos, however, Youtube partners are able to upload their own custom thumbnails.
However, doing a little searching apparently there's a grey-hat way to do this for non-partner, but there's a pretty big risk in using this method since Youtube could ban your account: Custom Thumbnail for Non-Partners