A release without promo graphics is a release nobody hears about. Announcement, release day, a story graphic people can reshare — that's the minimum, and it works.
Each graphic is designed for the platform it's going on, because a feed post cropped into a story looks exactly like a feed post cropped into a story. If we designed your cover, these will carry the same visual language automatically.
If you need three or more, the Social Graphic Package is $75 for a coordinated set and saves you money over ordering individually.