Any computer user today is familiar with the term JPEG - a very popular image file format containing compressed image data. JPEG or Joint Photographic Experts Group is technically, a method to compress bitmap images or photographic images. Depending on the requirements of the user, one can select the degree of compression. There are two important factors to be considered while compressing the images the quality of the image and the storage size. JPEG typically achieves 10:1 compression with little perceptible loss in image quality.
Though a popular compression format, it is advisable to not use it for compressing data that needs to be a total visual representation of the original. However, it is one of the best formats to be used for photographs clicked by a digital camera. There are two compression methods used with JPEG Lossy and Lossless. A JPEG Lossy compression method is one in which some information is removed from the parent image it must not be used in astronomical or medical imaging or other purposes where the exact reproduction of the data is required. Lossless formats such as PNG must be used instead. A JPEG Lossless compression method provides a way to alter an image in a number of ways in order to compress the image data without adverse affecting the quality of the image.
A certain interlaced "Progressive JPEG" format is used for displaying images on a computer using a relatively slow connection speed from network locations. In this method, the data is compressed in multiple passes of progressively higher detail. This provides the ability to display a reasonable preview after receiving only a portion of the data. However, progressive JPEGs are not as widely supported, and even some software which does support them only displays the image once it has been completely downloaded. There are also many medical imaging systems that create and process 12-bit JPEG images. The 12-bit JPEG format has been part of the JPEG specification for some time, but again, this format is not as widely supported.