I have a problem when using Safari/OSX and the offset option: The images in the view port do not get loaded on document.ready.
In my case I used offset: 200 and while the images in the view port appear on my Desktop PC using Chrome, IE or Firefox, they do not appear on my MBP Retina using the latest Safari browser. Only after scrolling up and down and having loaded all the other images, they appear.
I called the plugin like this:
jQuery(document).ready(function() {
var bLazy = new Blazy({
selector: '.thumbnail',
offset: 200
});
});