Loading a Bufferedimage

Greetings.

I seem to be having trouble loading a BufferedImage as a Class folder.
Essentially, I have these pieces of code in my ArtResources class :

public static Bitmap walltest = loadBitmap("/focus/Resources/textures/walltest.png");


	
	public static Bitmap loadBitmap(String filename){
		try {
			System.out.println(System.getProperty("java.class.path"));
			BufferedImage image = ImageIO.read(ArtResources.class.getResource((filename)));
		etc.
}

According to the getProperty() line, my class path is : D:(…)\TimeStrips\bin

My resources are in a /src/Resources/textures folder. What am I doing wrong exactly ? No matter what path I specify, and which folder in the hierarchy I set as Class folder still yields me a java.lang.IllegalArgumentException: input == null! error.