/*
          +----------------------------------+                
          |  IListImageFile                  |                
          +----------------------------------+                
          | boolean contains(ImageFile that) | 
          +----------------------------------+                
                         |                    
                        / \                   
                        ---                   
                         |                    
           ---------------------------          
           |                         |          
  +----------------+     +-------------------+  
  | MTListImageFile|     | ConsListImageFile |  
  +----------------+     +-------------------+  
  +----------------+  +--| ImageFile first   | 
                      |  | AList rest        |   
                      |  +-------------------+ 
	            		    v
                +---------------+    
                | ImageFile     |    
                +---------------+    
                | String name   |     
                | int    width  |      
                | int    height |      
                | String kind   |      
                +---------------+    

 */  

//to represent a list of ImageFile objects
public interface IListImageFile{
  
  // does this list contain that ImageFile
  public boolean contains(ImageFile that);
}