Bug 119220 Image in library can't display properly when it is imported in a report design.
Description: Image in library can't display properly when it is imported in a report design. Steps to reproduce: 1. Add an image in a library. 2. Use this library in a report design. 3. Drag the image from library explorer into layout view. 4. The image is marked invalid.
model/org.eclipse.birt.report.model/src/org/eclipse/birt/report/model/api/ImageHandle.java
* <li><code>IMAGE_SIZE_SIZE_TO_IMAGE</code>
	 * <li><code>IMAGE_SIZE_SCALE_TO_ITEM</code>
	 * <li><code>IMAGE_SIZE_CLIP</code>
	 * </ul>
	 * 
	 * @return the internal value of the image size.
	 */
	public String getSize( )
	{
		return getStringProperty( ImageItem.SIZE_PROP );
	}
	/**
	 * Returns the alternate text of this image.
	 * 
	 * @return the alternate text of the image item.
	 */
	public String getAltText( )
	{
		return getStringProperty( ImageItem.ALT_TEXT_PROP );
	}
	/**
	 * Returns the resource key of the alternate text of this image.
	 * 
	 * @return the resource key of the alternate text
	 */
	public String getAltTextKey( )
	{
		return getStringProperty( ImageItem.ALT_TEXT_KEY_PROP );
	}
	/**