The ".jpg" file format, short for Joint Photographic Experts Group, is a widely used method for compressing digital images. It is popular because it reduces file size while maintaining acceptable image quality, making it ideal for sharing and storing photos on the internet. This format supports millions of colors and is commonly used for photographs and complex images. However, it uses lossy compression, meaning some image data is lost during the compression process, which can affect quality if the image is edited and saved multiple times.