drill down in bullets

drill down in bullets

Is there a way to include a picture or pdf under a bullet point to make it drill down like the regular bullets.

For example,
  1. Main bullet
    1. Sub bullet 
    2. Sub bullet 
    3. Sub bullet 
    4. Sub bullet 
In this example I am able to hide and show the sub bullets

But if I do
  1. Main Bullet
PDF / Picture

In this example, I am not able to put pdf or picture inside the sub bullet to be able to hide and show.