Q. What happens when I set rendering properties - such as object color or highlights - on an image?

Is the color of the image determined by the color value you set for it or by the data?

A. Some object properties will affect the image, others won't. The color property will not be used; the color for an image is always taken from the pixel data (because a special ID is set on in the Field's node_data component). The same is true for specular highlights. But you can set the ambient and diffuse lighting properties for the image and they will be applied. You can also set lines and points modes and set the color of the lines and points.