The full form of JPEG is Joint Photographic Experts Group, the name of the committee which created JPEG format and other still picture coding standards. Commonly used approach of irreversible compression for digital photos.
JPEG is the most common image format used now a days used by digital cameras and other image capturing devices. It specifies the codec, how an image is compressed into a stream of bytes and decompressed back into an image however the file format which contained that stream is changed.
Uses of JPEG
JPEG file compression is best suited for photographs and paintings of real world with smooth variations of tone and colour. Its is the best format for internet usage where data is required to be of reduced amount for responsive presentation. Its easy and efficient approach of compressing image file therefore beneficial use of JPEG makes it popular.
Image file formats like JPEG/ Exif/JPG are the standardized means of organising and storing digital image. Image file format can store data uncompressed, compressed or in vector format. Once rasterized, digital picture becomes a grid of pixels.
Every pixel has a number of bits to assign its colour equal to the colour intensity of the device displaying it.
JPEG is typically used as irreversible compression method, which reduces the degree of exactness of the image, it is inappropriate for reproduction of the exact image. Every time a file is compressed using the JPEG format, quality of the image is reduced each time.
Despite that image sizes are immensely reduced in JPEG format. JPEG image holds success in maintaining a reasonable image quality. Its unique compression feature allows the file format to be transferred and shared widely over the Internet in a quick and efficient way.
Also, a vast number of JPEG files can be stored in minimum space. Images can also be converted into JPEG via lossless compression. Digital cameras, software’s like paintshop pro use JPEG format generally for storing the compressed images.
There are two types of image compressions:
Lossless compression & Lossy compression (Irreversible compression)
Lossless compression, its reduces the file size while preserving the precise copy of original uncompressed image. This compression commonly concludes in larger image sizes as compared to lossy compression, however, not all the time.
Lossy Compression, while compressing file using lossy algorithms apparently preserves a representation of the uncompressed image, which might appear like the original image, but it is not exactly original. Irreversible compressions results in often smaller size of file compared to lossless compressions.
JPEG compressed image are generally stored in JFIF (JPEG file interchange format). File extension for JPEG file is JPEG or JPG. Every digital camera which supports 8-bit grayscale image and 24-bit colour images can save images in JPEG/JFIF format.
JPEG allows both image compressions; lossy and lossless compression. However, Lossless compression is not widely supported therefore lossy compression is used commonly to convert an image in JPEG format.