Q:
A: Not sure what you mean by plugging, but no substantial weight should be hung on a drywall or plaster wall unless the fastener is into a wall stud. Molly bolts and hollow wall anchors have there uses, but can't replace the structural strength of a wall studs. If there is too much weight on an anchor, it will pull through and might take a big chunk of wall with it. But, the wall studs might not be in the exact place needed if you wanted to, let's say, center a painting over a couch. A remedy, and this was very common in pre 1950's homes, is to install "picture rail" on the walls just below the ceiling. You normally leave a gap of an inch or so between it and the ceiling. This decorative wood trim is nailed into the studs, which spreads the weight over an entire wall, rather than a little hole in the plaster. You can even hang a plasma tv or lcd tv from it if properly installed, saving the $150 cost of a wall bracket. You then attach wires to your heavy picture, and adjust the height before hanging it on the rail. A nice feature is you can move pictures right or left an inch or ten feet, which is nice if you move furniture around once in awhile. You can also change your artwork often without making it into a big project. If you can read a tape measure, have a level, can use a coping saw, and hammer a nail, you can install it yourself. It is old in the millwork/trim departments at all home centers or lumber yards