https://pattern-making.com/wp-content/themes/blanco/js/tooltip.js?ver=7.1.2

1function imageTooltip(el) {
2var dw = jQuery(window).width(),
3		dh = jQuery(window).height(),
4	iw, ih, pt, pl;
5
6	jQuery('.imageHolder').remove();
7	jQuery('body').append('<div class="imageHolder"></div>');
8	jQuery('.imageHolder').css('position', 'absolute').css('display', 'none').css('zindex',10001);
9
10	el.each(function() {
11		jQuery(this).hover(function (e) {
12			var el = jQuery(this),
13			src = el.attr('id'),
14			img = new Image();
15			dh = jQuery(window).height();
16			dw = jQuery(window).width();
17			dh = jQuery(window).height();
18			el.css('cursor', 'progress');
19			jQuery('.imageHolder img').remove();
20			jQuery(img).load(function () {
21				el.css('cursor', 'default');
22				jQuery('.imageHolder').append(this);
23				iw = jQuery('.imageHolder').width();
24				ih = jQuery('.imageHolder').height();
25				//check if image larger than dh
26				if (ih > dh) {
27					jQuery('.imageHolder img').height(dh-40);
28					ih = dh-40;
29				}
30				//check if image larger than dw
31				if (iw > dw) {
32					jQuery('.imageHolder img').width(dw-40);
33					iw = dw-40;
34				}
35			}).error(function () {
36						alert('Error loading image.');
37					}).attr('src', src);
38		},function () {
39			//jQuery('.imageHolder img').fadeOut(300, function() {jQuery(this).remove()});
40			jQuery('.imageHolder img').hide().remove();
41		}).mousemove(function (e) {
42					ih = jQuery('.imageHolder').height();
43					iw = jQuery('.imageHolder').width();
44					//if image height not fits to bottom
45					var out = e.pageY+ih-jQuery(document).scrollTop()-dh;
46					//check if image not fits to window
47					if (e.pageY+ih-jQuery(document).scrollTop()>dh) {
48						jQuery('.imageHolder').css('top', e.pageY-out-20);
49					} else {
50						jQuery('.imageHolder').css('top', e.pageY-20);
51					}
52					//check if image on the right and not fits
53					if (e.pageX+iw > dw-20) {
54						jQuery('.imageHolder').css('left', e.pageX-iw-20);
55					}
56					else {
57						jQuery('.imageHolder').css('left', e.pageX+20);
58					}
59					if (!jQuery('.imageHolder').is(':visible')) {
60						jQuery('.imageHolder').fadeIn(200);
61					}
62				});
63	})
64}