Jquery lazyload with ajax

Shortly, the best optimized way to do this is to call the lazyload in your ajax's success function:

$.ajax({
    url: "your url here",
    type: "Post",
    success: function(response){
        // handle your success callback here
        $("img.lazy").lazyload({ 
              effect : "fadeIn"
        });
    }
});

---

But if you want to centralize your call to the lazyload plugin, you have 2 options:

First: (not recommended due to performance hit)

$(document).on('DOMNodeInserted', '#container', function() {
    $("img.lazy").lazyload({
        effect: 'fadeIn'
    });
});

but note here the "#container", it is the container's selector where you will show your new loaded stuff, so the code above will listen inside this container for any newly added stuff to run the lazyload again on new images,

Second: (recommended)

Calling your custom lazyload by adding it to your JQuery:

$.fn.myLazyLoad = function() {
    this.lazyload({ 
          effect : "fadeIn"
    });
};

then, call it in all your AJAX requests:

$.ajax({
    url: "your url here",
    type: "Post",
    success: function(response){
        // handle your success callback here
        $("img.lazy").myLazyLoad();
    }
});

NOTE: At the time this answer was accepted, this worked. The lazy loading plugin changed and now it is broken. I cannot unaccept the answer nor can I delete it.

There is another Q&A that suggests handling it as part of the AJAX request responsible for inserting the additional DOM:

Binding image lazy loading to new images inserted after ajax request

However, this is how I would do it:

$(document).on('DOMNodeInserted', 'img.lazy', function() {
    $(this).lazyload({
        effect: 'fadeIn'
    });
});

Demo: jsfiddle