Like commercials, promos run regularly in the broadcast screen area, side, or bottom areas of your VMcast. They are independent of your loops. So even if you change out your loops, these promos will still play.
These promos run in the same area as your VMcast broadcast loop. You set how often your promos run. For example, you can set your promo to show after every three loop items. Main-screen promos can be images or video. Videos should be H.264 format 1080p or 720p and images should be jpeg or png format 1920px wide by 1080px deep.
Any promo can be set as a Universal Promo. Universal promos run on all of your streams along with any stream-specific promos that have been set. So if you want something to show on all streams, make it Universal instead of going to each stream and making separate promos.