JPEG is a very popular image file format, its full form is ” Joint Photographic Experts Group .” At the same time it is commonly used to store photos by digital cameras because it supports 224 or 16,777,216 colors.
This format supports compression of many levels, which makes it ideal for web graphics. These 16 million possible colors are produced in a JPEG image, using 8 bits of each color (red, green, and blue) in the RGB color space.
It provides 28 or 256 values for each of these three colors, which together allow 256 x 256 x 256 or 16,777,216 colors.
Three values of 0 produce pure black, while three values of 255 produce pure white.
These JPEG compression algorithms can easily reduce file size by ten times that of a bitmap (BMP) image, almost without any degradation in quality.
The compression algorithm is lossy, which means that some image quality is lost during the compression process.
This is the reason, professional digital photographers often choose the raw format for capturing images so that they can edit their photos in the highest quality possible. They typically export pictures to JPEG ( .JPG ) images when they share or publish them in the web .
In addition to image data , JPEG files include metadata that describes the contents of that file. This includes image dimensions, color space, and color profile information, along with EXIF data.
These EXIF data is often ” stamped ” into the image by a digital camera and includes aperture setting, shutter speed, focal length, flash on / off, ISO number, and many other values.
JPEG Format के Disadvantages
Where JPEG format is very good for storing digital photos, it also has some drawbacks.
For example, some issues arise from these lossy compression such as ” artifacting ,” in which parts of the image appear to be noticeably blocky. This often happens when a high compression setting is used to save the image.
While the small image and such images which have a lot of text, then GIF format is used in such a better way. JPEG images also do not support transparency.
Thus JPEG format is a bad choice to save non-rectangular images, especially if they are published in webpages with different background colors.
In these cases the PNG format, which supports transparent pixels, is more ideal for these types of images.
NOTE : This Joint Photographic Experts Group, which is the JPEG image format, published their first JPEG specification in 1992.
Since then, this organization has developed a wide variety of variations, including JPEG 2000 and JPEG XR. But standard JPEG format has been very popular till date.
File extensions: .JPG, .JPEG, .JFIF, .JPX, .JP2