Hanging Picture Over Fireplace . Starting with the bottom row: Centre the first frame in the middle of the mantle, and once it is in the right spot, push into the wall to hang it. 25 Cozy Ideas for Fireplace Mantels Southern Living from www.southernliving.com If the mantel is four feet or taller, then hang four to six inches above. The mortar holding the stone is recessed probably 4 or so, leaving crevices between the rocks on the face of the chimney. If the artwork (or mirror) is taller than three feet, lean it on the mantel.