With this test code I can access images pasted to the site

document.onpaste = function (event) {
    var items = (event.clipboardData || event.originalEvent.clipboardData).items;
    for (index in items) 
    {
        var item = items[index];
        console.log(item);
        console.log("________");
    }
}

but when I copy file from file system

then it isn't being caught

how can I catch e.g gifs too?