Over time your oil breaks down and your filter becomes clogged with contaminants. You have to change your car´s oil periodically to flush these contaminants out of the system. The contaminants which appear in photos are called artifacts; their presence is a clear sign that something is wrong in the image.
In the best case scenario, you wouldn’t need to interpolate your images because you would be shooting with a camera that renders a 50MB file. If you do have to interpolate, you should carefully check the image at 100% to verify that it hasn’t become “pixelated,” mottled, or filled with wormy looking artifacts. This happens when the software doesn’t have enough information in a given area of the image to enlarge it, and so begins to invent information, in the form of obvious looking, one toned pixels.
The JPG format is ideal for the transmission of images because it is versatile, lightweight, and has little perceptible quality loss in the image. We recommend that you retouch your images in RAW/Tif and create the JPG only when you are finished. Otherwise, a JPG file which is repeatedly open and adjusted will lose quality and become pixelated, meaning that the pixels begin to appear as small individual color blocks that stand out, rather than fuse together.
Example. Here you can see examples of the pixelated effect in the image definition. The colors and texture don’t show continuous, subtle variations, but have become little color blocks, that stand out from the color and texture of the surrounding areas.