Format name: JPEG (Joint Photographic Experts Group)
Extension: jpg, jpeg, jfif,jfl
Type: bitmapped
Compression algorithm: JPEG (lossy)
Color depth: 24 bits
Platforms: all
Jpeg format was designed to transfer graphic data and images via digital telecommunication
networking and was generally used to hold and transfer full color photorealistic
images. Before Jpeg, there were very few formats, which supported 24 bit halftone
images. TIFF and BMP formats allowed holding 24 bit data, but they failed to
perform a lossless compression of the data, which contained thousand colors
from the real world, on the high quality level.
Jpeg compresses photos though with quality loss. Compression algorithm is that data are deleted for deallocation (it allows to raise the compression degree). Data are hold as pixel block in a certain color with intensity information save (the matter is that a human eye discerns disintensity better than discoloration).
Photos and multi-color images, transferred in this format, are ideal for networking.
It is not possible to refine Jpeg images, though it is possible to debase them by decreasing the file size.
Jpeg format is primarily used to hold photorealistic graphic images with a large number of colors.
Compressed data capacity depends on image contents. Compression degree may come up to 25:1 without visible loss in quality.
Jpeg supports Progressive Jpeg standard, which conceptually looks like interlaced
in Gif format. That means that Jpeg Progressive format images are loaded by
parts, which are displayed, as they are loaded. Such format is good for large
files. Unfortunately, it is a new standard, so some programs may not support
it.