Uploading pictures to your event page's media gallery is a great way to give event goers a little taste of what your event is all about.
Hover over the Tools tab, and select Media Galleries.
Click the Create a New Media Gallery button to create your first gallery. Now, give it a name.
Now you can either drag and drop your picture files or select images to upload. Just a heads up, image files cannot be larger that 5 MB in size and must be JPG, GIF, PNG or TIF format.
Once the photos have finished uploading, you can assign the media gallery to any of your events. Go to the event and scroll down under the Details tab to choose which gallery to assign to each event.