IEI Technology ISIGNAGER - 800WL-N270, Руководство пользователя

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iSignager-800WL-N270 Digital Signage Player
Page 40
A.3 Overview of Graphic Formats
A.3.1 JPEG and JPG
JPEG (pronounced as jay-peg) is a commonly used standard method of lossy
compression for photographic images. JPEG is designed for compressing full-color or
gray-scale images of natural, real-world scenes. It works well on photographs, naturalistic
artwork, and similar material; not so well on lettering, simple cartoons, or line drawings.
The file format which employs this compression is commonly also called JPEG; the most
common file extensions for this format are .jpeg, .jfif, .jpg, .JPG, or .JPE although .jpg is
the most common on all platforms.
A.3.2 BMP
The name is short for bitmap and these files can be saved at various bit-depths. It is a
bitmapped graphics format used internally by the Microsoft® Windows® graphics
subsystem (GDI), and used commonly as a simple graphics file format on that platform.
Images are generally stored with a color depth of 2 (1-bit), 16 (4-bit), 256 (8-bit), 65,536
(16-bit), or 16.7 million (24-bit, referred to as true-color) colors (the bits represent the bits
per pixel). 8-bit images can also be gray scale instead of indexed color. 24-bit BMP
files are lossless but are much larger in file size than JPEGs.
A.3.3 GIF
GIF (Graphics Interchange Format) is a bitmap image format for pictures with up to 256
distinct colors from the over 16 million representable in 24 bit RGB.
A GIF file employs lossless data compression so that the file size of an image may be
reduced without degrading the visual quality, provided the image fits into 256 colors.
Therefore GIF is normally used for diagrams, buttons, etc., that have a small number of
colors, while the JPEG format is used for photographs.
A.3.4 PNG
PNG (Portable Network Graphics) is a lossless compressed bitmap image format. PNG
was created to both improve upon and replace the GIF format with an image file format not
requiring a patent license to use. PNG is officially pronounced "ping" and, like GIF and