The Feature Image section on an event allows you to add a suitable image. These images should not contain any text, as this should be included in the about section. The image should complement the written content. Also be aware that screen readers (as used by the visually impaired) cannot read images.
If you don’t have your own images to promote an event or service, there are many available for free on the Resource Hub. For more information about sourcing images, there are two Labs Learning Blogs on the Church of England website that could help: Building your photography library and taking great photos.
See these following examples of suitable images to use with your events: