Introduction
Images, except GeoTIFFs, are imported with no geospatial reference, which means that they will be displayed in origo if they are not geo-referenced first. Since your data most likely will not be located around origo, you need to geo-reference the image before displaying it. Read more about: Images and Georeferencing
On this page:
Displaying an image
Images are displayed by executing the Display 
command.
Draping images on terrain
Before you drape an image on to the terrain, make sure that the image is georeferenced and in the same projection as the terrain. Use the Map image on terrain command, which can be found in the Additional display folder. In the menu you will have to select which terrain the image should be draped on.
Displaying a vertically calibrated image
Vertically calibrated images can be displayed using the regular Display command, presuming the image is of the type Vertical Calibrated Image (look at the Type column in your project). Read more about how to vertically calibrate an image