How to show an image for each event on the timeline

To attach an image:

1. First open the appropriate item in the Inspector and then go to the Attachments and Link tab: 
2. Under the Image heading, click "Attach Image" or "Link to Image" to add your image.
3. Go to the footer in the Timeline View and click the  icon.
4. In the popover menu, ensure that 'Image' is ticked. The images attached to items in your timeline should then be visible in your view. 

You can read in more detail about about adding images in the detailed article [Images, Attachments and Links] we have written. Essentially, you can add an image as either an attachment or a link. The difference is that if added as an attachment, the file will be embedded within your timeline.There will be a primary image for each item you attach images to, and this will be the item that is visible in your timeline.