Search:

public class MyClass{
private int myClassVariables;

public MyClass(){
} // Constructor

public int myIntReturningFunction(){
return 2;
...

Well if Picture is your own class then you can just add the methods into it, it's hard to see exactly what is going on.

Chris

well i assume you have made edgeDetection part of the Picture class, and well that error is suggesting that you should be passing a DOUBLE not an INT ;)