JPEG

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JPEG

Computing a standard file format for compressing pictures by disposing of redundant pixels

JPEG

[′jā‚peg]
(graphic arts)
Graphics file format for compressed still images, particularly photographic images found on the World Wide Web; developed by the Joint Photographic Experts Group.

JPEG

JPEG

(Joint Photographic Experts Group) An ISO/ITU standard for compressing still images. Pronounced "jay-peg," the JPEG format is very popular due to its variable compression range. JPEGs are saved on a sliding resolution scale based on the quality desired. For example, an image can be saved in high quality for photo printing, in medium quality for the Web and in low quality for attaching to emails, the latter providing the smallest file size for fastest transmission over slow connections.

Not Great for Text
JPEGs are not suitable for graphs, charts and explanatory illustrations because the text appears fuzzy, especially at low resolutions. Compressing images in the GIF format is much better for such material (see GIF).

JPEGs Are Lossy
Using discrete cosine transform, JPEG is a lossy compression method, wherein some data from the original image is lost. It depends on the image, but ratios of 10:1 to 20:1 may provide little noticeable loss. The more the loss can be tolerated, the more the image can be compressed.

Compression is achieved by dividing the picture into tiny pixel blocks, which are halved over and over until the desired amount of compression is achieved. JPEGs can be created in software or hardware, the latter providing sufficient speed for real-time, on-the-fly compression. C-Cube Microsystems introduced the first JPEG chip. See JPEG2000, JPE file and GIF.

File Extensions
JPEGs use the JPEG File Interchange Format (JFIF), and file extensions are .JPG or .JFF. M-JPEG and MPEG are variations of JPEG used for full-motion digital video (see MPEG). See graphics formats.


Saving JPEGs
At first glance, these two dialogs seem contradictory because the larger number means high quality in one and low quality in the other. Photoshop (top) uses a 1-to-12 scale for quality, while Epson (bottom) uses a percentage for the amount of compression. The more compression, the more loss in the result. Standard is the original JPEG format, while Optimized compresses more effectively. Progressive causes the image to display incrementally from top to bottom. Web users with slow connections see the image form on screen right away rather than wait for the entire file to download first.


Saving JPEGs
At first glance, these two dialogs seem contradictory because the larger number means high quality in one and low quality in the other. Photoshop (top) uses a 1-to-12 scale for quality, while Epson (bottom) uses a percentage for the amount of compression. The more compression, the more loss in the result. Standard is the original JPEG format, while Optimized compresses more effectively. Progressive causes the image to display incrementally from top to bottom. Web users with slow connections see the image form on screen right away rather than wait for the entire file to download first.
References in periodicals archive ?
The JPG file is created from the TIFF, but because this file type uses lossy compression it cannot be used as an archival copy.
In the window that appears, find and click on Internet Explorer (or IEXPLORE) and check the box at the bottom labelled "Always use this program." If the file you clicked was a JPG file you'll have to do the same with a GIF file (or vice versa).
Remember to send all digital photos in a jpg file format with a resolution of 300 dpi.
In its current form, an infected jpg file sent to a friend or placed on a Web site isn't dangerous without the extractor file.
While the microscope package did come with its own graphics package, it was somewhat limited and it seemed a waste of time to look at it in any detail as the JPG file can be viewed and edited with essentially any graphics package to enhance or adjust the colours, brightness or contrast.
Secondly, the final JPG file generated by the camera has significant JPG compression, leading to smudging of finer details like texture.
The jpg file sizes shown are those that should be produced by the camera, and it is these I need for the Journal.
The creation can be uploaded to a Flickr account, saved as a JPG file, e-mailed, or printed for purchase.
The final dynamic range in the JPG file from the wide-angle camera barely managed to hold it together, but if you want the most out of the sensor, you will have to resort to some editing to boost the shadows.
RAW files will give you a lot more latitude in edits than a JPG file. You will also always get more detail from a RAW file than you would a JPG, so if that's a critical point for you, then RAW is the way to go, even though each file weighs about 80MB.
In the end, all applicants must have 1 jpg file and 2 pdf files.
Voting results can be automatically printed after each vote or saved as a JPG file and printed later