Give this a try. In your gallery.js file you can comment out the tooltip code to hide the functionality. Just note that this will hide the tooltips on desktop browsers as well - this isn't a responsive solution so media queries won't come into play here. I don't believe your site is responsive anyway. If you're comfortable with this, replace lines 113 thru 127 with the following:
/* this.tips = new Tips(this.thumbs.images, {
className: 'pg-gf-tip',
offset: {'x': -100, 'y': -105},
showDelay: 1,
hideDelay: 1,
onShow: function(tip) {
this.options.offset.y = this.tip.getSize().y * -1 - 15;
this.tip.setStyle('top', (pgMousePosition.y + this.options.offset.y) + 'px');
this.tip.fade('show');
},
onHide: function(tip) {
this.tip.fade('hide');
this.tip.setStyle('top', '0px');
}
}); */
If you want to bring the tooltip functionality back, remove the /* */ at lines 113 and 127 that I added. Lastly, I'd suggest that you make a backup of the original gallery.js file before making any modifications to it. It can be a life line if something goes wrong and you need to go back to the original code. Hope this can help.