private void checkLoaderRow(){
			if(imgRow < 0){
				throw new IllegalArgumentException(String.format("Illegal row specified, must be a non-negative number (yours was %d)", imgRow));
			}
			if(null != ldr && !(ldr.numColumns() > imgRow)){
				throw new IllegalArgumentException(String.format("Illegal row specified, largest legal row is %d (yours was %d)",ldr.numRows() - 1, imgRow)); 
			}
		}