It depends on what type of lamp is in the fixture. I used to run into this issue occasionally working at a lighting showroom. The answer can be as simple as making sure you use a light bulb with the correct voltage. No need to change wires, etc. Bulb just needs to be the same voltage to be compatible...this is typical for your standard incandescent light bulbs like an A-lamp...or Edison lamp. This is NOT going to be the case if you have low voltage fixture a transformer involved. In that case you would have to change out the transformer to one capable of handling a different voltage load. Stick with line voltage fixture, and simply making sure the bulb you use has the right voltage, it's a pretty simple fix.

Paint that wall behind the fireplace! A deep gray to pull out the grey/slate color in the brick. This will give you a blank canvas and accentuate that fireplace. Paint the mantel a creamy white to match the cream in the brick. Use simple accessories on mantel, no pictures with the TV. I would suggest a taller vase and lower potted green on one side. Maybe a slimmer vase on the other. Paint all walls grey, but use lighter that fp wall. Get rid of all the dark pillows and use creamy colored pillows with slipcovers for easy cleaning. (looks like there are young kids who live here too) Then add a couple accent pillows for color. I would replace that coffee table with a creamy leather (or pleather) ottoman. It can be used as a coffee table when needed by adding a tray. The rest of the time, it is a soft landing for young kids and a comfy place for your feet. :)

I have two ideas, one is a white globe lamp, the other is a modern track system that will help you high light the art and fireplace. either will work. the ones i pictured are from Ikea, but im not sure if you have access to them. or a lighting showroom?

My light casts it's frame shadow, but it's not that noticeable because it's way up high (see pic) mine is in a double floor height ceiling. I think if the pendant was lower, then shadows would be more prominent. Also, my light isn't as busy, so the shadows are less. Overall, my take is the busier the pendant and lower the height, you'll see more shadows. (don't mind the paint job, still in reno)