firepad-drag-drop-images.js

    codeMirror.setOption('onDragEvent', function(cm, e) {
        // Move the cursor as they drag.
        var pos = codeMirror.coordsChar({left: e.x, top: e.y });
        codeMirror.setCursor(pos);
        codeMirror.focus();

        var isImageDrop = e.type == 'drop' && e.dataTransfer.files && e.dataTransfer.files.length > 0 && e.dataTransfer.files[0].type && e.dataTransfer.files[0].type.indexOf('image/') > -1;
        if (!isImageDrop) return;
        event.preventDefault();

        var reader = new FileReader();

        reader.onload = function(event) {
            var img = new Image();
            img.onload = function () {
                firepad.insertEntity('img', {
                    'src' : event.target.result,
                    'width' : this.width,
                    'height' : this.height
                });
            };
            img.src = event.target.result;
        };

        reader.readAsDataURL(event.dataTransfer.files[0]);

        return true;
    });