Photoshop Elements :: Image File Sliced - How To Reassemble All The Parts

I have an image file that was created in Photoshop.  It was sliced into buttons and parts of buttons.   I am trying to reassemble all the parts in Photoshop elements.  I drag and drop the parts onto the canvas.  I turned on the grid.  I noticed that each part I drop onto the canvas creates a new tab and what looks like a new layer.  I don't want this.  I would like to import all the parts of the button images and reassemble them on one canvas.   I have imported the images into the organizer but it seems like I can only drag and drop the image parts one at a time onto the canvas.