Painting Shows Missing Son Behind Mirror Screaming

by Katie
(USA)

This movie was most likely made in the late 80's or early 90's.

A family moves to a house and a little boy is taken by something in the house. The father has no idea where his son is until he looks at a painting his mother is working on. It shows a room (bathroom?) with a mirror in it, and his son is pressed against the mirror, screaming. The father breaks the mirror and pokes his head through to see a dark chasm with demons flying around everywhere.

At some point, someone drowning in the pool disappears when they're taken away by demon creatures.

Any ideas on the title?