If they are oil then wrap in soft tissue or kitchen roll first, otherwise wrap them in bubble wrap at least 2 or 3 times around. I would place a piece of cardboard over the glass before wrapping in bubble if picture has glass.
Then either slide into a flat moving carton (meaning you haven’t taped it up into a cube yet) or buy picture boxes from a self storage place or from our moving supplies online. Slide the 2 pieces together over your bubble wrapped picture and tape them up using 2 inch packing tape. For more packing tips click here.