NOTE: ONLY ADMINISTRATORS CAN MANAGE EVENT PHOTOS IN YOUR EVENTS
As an event Administrator, you can select a new or existing event Photo to be displayed on the Photos tile of the Event Dashboard. To do this, you must first either select to add a new image or begin editing an existing event Photo. When you land on the 'Add Photo'/'Edit Photo' form, you will see the option 'Display This On The Event Dashboard?' displayed beneath the file upload button. Simply click on the checkbox provided and save your changes, and the image will now be displayed as a thumbnail on your Photos tile for the event.
To remove the default Photo from your Photos tile, you can either select a new image to become default by using the same process as described previously. Alternatively if you'd like to revert back to alphabetical ordering simply remove the tick in the checkbox when you next update the image.