Images can be assigned to preachers, series, and individual sermons. When displaying an image on your site, the first available image will be shown in this priority: featured image on the sermon, series image, and then preacher image.
To add an image to a preacher, go to Sermons → Preachers. Click the + sign or the blank image to upload a new image and associate it with the preacher. Follow the same process to add an image to a sermon series.