To reply to your comment:
First of all you are going to have to make your image into a prefab. This can be easily done by dragging the image file from the assets folder onto the scene view, then drag the newly made object back into the assets folder. (Delete the object in the scene if you want)
Now in order for the prefab to be able to accessed, you will have to create a new folder in your assets folder called "Resources". Put the GameObject prefab into this folder.
After that is done this code should do the trick:
private GameObject image;
public void Start() {
image = (GameObject)Resources.Load("Image1");
AddImage();
}
public void AddImage() {
Vector3 spawnPosition = new Vector3(0, 2, 0);
Quaternion spawnAngle = Quaternion.Euler(0, 0, 0);
Instantiate(image, spawnPosition, spawnAngle);
}