The more pixels your camera’s imaging sensor (CCD) is made of, the more likely some of them may fail. Think of the lights on a Christmas tree. When the string is smaller, the lights usually fire without incident. But the longer the set of lights, the higher the probability one or more individual lights will need repair. These “stuck,” “dead,” or “hot” pixels, as they are often called, can cause the quality of your images to be compromised. Nearly every digital camera, regardless of the manufacturer, includes a sensor that experiences this to some degree. The issue may not be severe enough to be noticed, but if you do notice this phenomenon to occur, look into Pixel Mapping.
Some digital cameras come with an Automatic Pixel Mapping function right inside the camera that helps prevent faulty pixels from affecting image quality. The feature can be manually selected from the camera’s menu and takes approx. 10-30 seconds to complete, depending on the camera model. By doing so, the location of the faulty pixels will be determined and stored to memory so the camera will automatically compensate for the missing information or incorrect data in subsequent exposures. It is recommended that this function be used at least once a year and if so, your camera should enjoy a much longer period of high-performance.
Check your digital camera's instruction manual to see if the Pixel Mapping feature is included. If not, you may be able to send it in to an authorized Olympus factory service center to have it done. Either way, your camera and the pictures you take using it will be better for it in both the short and the long run.