You can add an image or photo to an event if you are the event manager or system manager. The image would need to be hosted on an separate website, your web master should be able to assist you with this. 
To add the image follow the steps below:

1. Click the Manage Tab and Choose Manage Events
2. Locate the event you wish to add the image or photo
3. Click on the Pencil next to the event to edit the event
4. Under Event Information, Click on the insert image feature.
5. Enter the location of the image on the external website
6. Click ok.
7. Repeat for each image you want to add.
8. Click Save when done.

This can also be done during the initial creation of the event, by the following steps:

1. Under Event Information, Click on the insert image feature.
2. Enter the location of the image on the external website
3. Click ok.
4. Repeat for each image you want to add.
5. Click Save when done and publish if appropriate.