How do I get the coordinate position after using jQuery drag and drop?

I just made something like that (If I understand you correctly).

I use he function position() include in jQuery 1.3.2.

Just did a copy paste and a quick tweak... But should give you the idea.

// Make images draggable.
$(".item").draggable({

    // Find original position of dragged image.
    start: function(event, ui) {

        // Show start dragged position of image.
        var Startpos = $(this).position();
        $("div#start").text("START: \nLeft: "+ Startpos.left + "\nTop: " + Startpos.top);
    },

    // Find position where image is dropped.
    stop: function(event, ui) {

        // Show dropped position.
        var Stoppos = $(this).position();
        $("div#stop").text("STOP: \nLeft: "+ Stoppos.left + "\nTop: " + Stoppos.top);
    }
});

<div id="container">
    <img id="productid_1" src="images/pic1.jpg" class="item" alt="" title="" />
    <img id="productid_2" src="images/pic2.jpg" class="item" alt="" title="" />
    <img id="productid_3" src="images/pic3.jpg" class="item" alt="" title="" />
</div>

<div id="start">Waiting for dragging the image get started...</div>
<div id="stop">Waiting image getting dropped...</div>

Had the same problem. My solution is next:

$("#element").droppable({
    drop: function( event, ui ) {

        // position of the draggable minus position of the droppable
        // relative to the document
        var $newPosX = ui.offset.left - $(this).offset().left;
        var $newPosY = ui.offset.top - $(this).offset().top;

    }
});

I would start with something like this. Then update that to use the position plugin and that should get you where you want to be.