This is a small attempt to introduce some of the many image formats...
Image file
formats
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| Images!!!...there are many... |
Image file formats are standardized
means of organizing and storing digital images. Image files are composed of
pixels, vector (geometric) data, or a combination of the two. Whatever the
format, the files are rasterized to pixels when displayed on most graphic
displays. The pixels that constitute an image are ordered as a grid (columns
and rows); each pixel consists of numbers representing magnitudes of brightness
and color.
Image file sizes
Image file size—expressed as the
number of bytes—increases with the number of pixels composing an image, and the
color depth of the pixels. The greater the number of rows and columns, the
greater is the image resolution, and the larger is the file.
Also, each pixel of an image increases in size when its color depth
increases—an 8-bit pixel (1 byte) stores 256 colors, a 24-bit pixel (3 bytes)
stores 16 million colors, the latter known as truecolor.
Image compression uses algorithms
to decrease the size of a file. High resolution cameras produce large image
files, ranging from hundreds of kilobytes to megabytes, per the camera's
resolution and the image-storage format capacity. High resolution digital
cameras record 12 megapixel (1MP = 1,000,000 pixels / 1 million)
images, or more, in truecolor. For example, an image recorded by a 12 MP
camera; since each pixel uses 3 bytes to record truecolor, the uncompressed
image would occupy 36,000,000 bytes of memory—a great amount of digital storage
for one image, given that cameras must record and store many images to be
practical. Faced with large file sizes, both within the camera and a storage
disc, image file formats were developed to store such large images. An overview
of the major graphic
file formats follows below.
Image file
compression
There are two types of image file compression
algorithms: lossless and lossy.
1.
Lossless compression algorithms reduce file size without
losing image quality, though they are not compressed into as small a file as a
lossy compression file. When image quality is valued above file size, lossless
algorithms are typically chosen.
