You will need the Full Write Sermons permission to set a sermon series image.
Setting A Series Image
To give every sermon in a series the same image, open a sermon from Sermons in the left-hand navigation menu, hover over the image placeholder and click the pencil icon.
In the window, choose the series you want to edit and then toggle the Upload Image? field.
Upload the image and click Save. This becomes the image that a sermon in that series uses by default, unless a custom one is uploaded just for that sermon.
