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Picture Acronyms
Acronyms are words formed
from the initials or other
parts of several words. They are
prevalent in the computer world and can cause a lot of confusion. You may be aware of the acronyms
used for
picture files: JPEG or JPG (pronounced
JAYpeg); GIF (pronounced jiff or giff with the hard G sound); BMP
(pronounced
bitmap); PNG (pronounced ping); and TIFF or TIF. The
acronym you are most likely to encounter
is JPEG.
Most
of these
acronyms refer to a type of file compression. Uncompressed
picture files are enormous and infrequently
used. One example of this is TIFF files
which are
uncompressed and, thus, rarely used in computers because of the huge
amount of
time they take to download and the large amount of memory they use up. If a good friend sent you a TIFF file, you’d
probably go nuts waiting for the blasted thing to load on your system
(and
might want to reconsider your friendship).
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That’s why we
have file formats such as JPEG. JPEG
stands for Joint Photographic Experts Group (named
after the group
that invented the format). When a
picture file is converted to a JPEG with a .jpg extension, its size is
reduced
up to 95 percent. This is done by
selective omission of some pixels
(remember that a pixel is a unit of measure denoting a single dot of
color). Although codes are included that
allow some
of the deleted information to be restored, some definition is lost when
the
file is opened, thus JPEG is not as sharp an image.
JPEGs do, however, usually work well.
They support up to 16.7 million color shades. JPEGs
are
best for photographs, which contain lots of colors and curves. The drawback to JPEGs is that they can give
graphics a somewhat stair-stepped, primitive look.
GIFs (Graphics Interchange Format) don’t have
that problem but they only support 256 colors. For
this reason they’re not suitable for photographs. They
are, however, fine for Web graphics where you may not
need as
perfect an image as you would want on photographs.
PNG
(Portable
Network Graphics) was developed to circumvent royalty charges for GIF
compression. It has been
very slow to catch on. BMP (bit map)
images are used in Windows, are not sophisticated,
are also uncompressed (so they take up a
lot of room),
and are usually used for graphics rather than for pictures.
Source: www.komando.com
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