// set navigation images directory
ImageDir   = 'navigation-images/';

// define image names without extension

ImageNames = Array('back-off', 'back-on', 'capter', 'cat', 'cip', 'cit', 'cp', 'ct', 'ip', 'it', 'next-off', 'next-on', 'p', 'print-off', 'print-on', 't', 'view-index-off', 'view-index-on', 'zoom-in-off', 'zoom-in-on', 'zoom-out-off', 'zoom-out-on', 'zoom-zero-off', 'zoom-zero-on');

// default extension is .gif
ImageFileExtension = '.gif';

cat_images = Array();

for(i in ImageNames){
    
    cat_images[ImageNames[i]] = new Image();
    cat_images[ImageNames[i]].src = ImageDir + ImageNames[i] + ImageFileExtension;

}