There is now the option to add alternative images to your promo carousel blocks rather than using the pre-assigned programme thumbnail.

First navigate to ONE Admin > Content Management > Pages > Actions > Manage Content to create a video promo carousel for a Page

Create your promo carousel as you normally would, with 'Video Carousel' selected in the 'Type' dropdown.

When you add your selected programme, you will now have the option to select an image via the 'Alternative thumbnail' button.